Authorizes the Secretary of Health and Human Services to recognize the unique needs of high poverty areas in making grants for projects to plan and develop health centers to serve medically underserved populations.

Deems volunteer practitioners who provide medical services to patients at certain nonprofit health centers in underserved areas to be employees of the Public Health Service (thus extending the liability protections of the Federal Tort Claims Act to such practitioners).

Defines "volunteer practitioner" as a licensed physician, licensed clinical psychologist, or other licensed or certified health care practitioner in the state involved who provides services to patients of a health center without compensation or reimbursement at a health center site or a site designated by a health center.

Deems certain physicians or other licensed or certified health care practitioners to be employees of the Public Health Service for purposes of any civil action that may arise due to services provided: (1) in an emergency area during an emergency or a disaster; (2) by a contractor, volunteer practitioner, or an employee of a qualified health center; and (3) under an arrangement with such a center or with a federal agency responsible for providing health services in the emergency area.

Requires the Secretary of Health and Human Services to establish a demonstration project under which up to 30 qualifying integrated health systems receive grants for the costs of their operations to expand access to primary and preventive services for the medically underserved.

Requires the Comptroller General to study the economic costs and benefits of school-based health centers and their impact on the health of students, including an analysis of: (1) the impact that federal funding could have on the operation of such centers; (2) any cost savings to other federal programs derived from providing health services in such centers; and (3) the impact of such centers in rural or underserved areas.

Requires the Secretary of Health and Human Services, acting through the Administrator of the Health Resources and Services Administration (HRSA), to submit a report to the relevant congressional committees that describes efforts to expand and accelerate quality improvement activities in community health centers.

Requires the Administrator to establish a mechanism for the dissemination of initiatives, best practices, and other information that may assist health care quality improvement efforts in community health centers.

Directs the Comptroller General to study: (1) integrated health system models for the delivery of health care services to medically underserved and uninsured populations; and (2) the implications of extending Federal Tort Claims Act coverage to health care professionals who volunteer to furnish care to patients of health centers.

Authorizes the Secretary to recognize the unique needs of high poverty areas in making grants for projects to plan and develop health centers to serve medically underserved populations.

(Sec. 3) Reauthorizes appropriations for FY2008-FY2012 for: (1) the National Health Service Corps program; and (2) the National Health Service Corps Scholarship Program and National Health Service Corps Loan Repayment Program.

Repeals provisions requiring each center or clinic designated as having a health manpower shortage to demonstrate every six years that it meets the applicable requirements of the definition of a health professional shortage area.

Revises requirements for assigning members of the Corps to a health professional shortage area to require that the Secretary determine that an entity demonstrates willingness to support or facilitate mentorship, professional development, and training opportunities for Corps members.

Requires the Secretary to assist Corps members in establishing and maintaining professional relationships and developmental opportunities.

Includes the District of Columbia and U.S. territories as eligible jurisdictions under a grant program for states to provide educational loan repayment to health professionals in exchange for the provision of primary health services in health professional shortage areas. Reauthorizes appropriations for FY2009-FY2012 for such grants.

(Sec. 4) Reauthorizes appropriations for FY2008-FY2012 for grants for expanded delivery of health care services in rural areas, for the planning and implementation of integrated health care networks in rural areas, and for the planning and implementation of small health care provider quality improvement activities.

(Sec. 5) Reauthorizes appropriations for grants to help states develop and implement innovative programs to address the dental workforce needs of designated dental health professional shortage areas.

(Sec. 6) Requires the Secretary, acting through the Administrator, to: (1) provide guidance and technical assistance to health centers, state and local health departments, and emergency managers to integrate health centers into state and local emergency response plans and to better meet the primary care needs of populations served by health centers during public health emergencies; and (2) encourage employees at health centers to participate in emergency medical response programs.

(Sec. 7) Amends title XVIII (Medicare) of the Social Security Act to revise the definition of "rural health clinics" to extend from three years to four years the time frame for making certain designations related to a shortage of health services in an area.

Health Care Safety Net Act of 2008 - (Sec. 2) Amends the Public Health Service Act to reauthorize appropriations for FY2008-FY2012 for health centers to meet the health care needs of medically underserved populations.

Requires the Comptroller General to study the economic costs and benefits of school-based health centers and their impact on the health of students, including an analysis of: (1) the impact that federal funding could have on the operation of such centers; (2) any cost savings to other federal programs derived from providing health services in such centers; and (3) the impact of such centers in rural or underserved areas.

Requires the Secretary of Health and Human Services, acting through the Administrator of the Health Resources and Services Administration (HRSA), to submit a report to the relevant congressional committees that describes efforts to expand and accelerate quality improvement activities in community health centers.

Requires the Administrator to establish a mechanism for the dissemination of initiatives, best practices, and other information that may assist health care quality improvement efforts in community health centers.

Directs the Comptroller General to study: (1) integrated health system models for the delivery of health care services to medically underserved and uninsured populations; and (2) the implications of extending Federal Tort Claims Act coverage to health care professionals who volunteer to furnish care to patients of health centers.

Authorizes the Secretary to recognize the unique needs of high poverty areas in making grants for projects to plan and develop health centers to serve medically underserved populations.

(Sec. 3) Reauthorizes appropriations for FY2008-FY2012 for: (1) the National Health Service Corps program; and (2) the National Health Service Corps Scholarship Program and National Health Service Corps Loan Repayment Program.

Repeals provisions requiring each center or clinic designated as having a health manpower shortage to demonstrate every six years that it meets the applicable requirements of the definition of a health professional shortage area.

Revises requirements for assigning members of the Corps to a health professional shortage area to require that the Secretary determine that an entity demonstrates willingness to support or facilitate mentorship, professional development, and training opportunities for Corps members.

Requires the Secretary to assist Corps members in establishing and maintaining professional relationships and developmental opportunities.

Includes the District of Columbia and U.S. territories as eligible jurisdictions under a grant program for states to provide educational loan repayment to health professionals in exchange for the provision of primary health services in health professional shortage areas. Reauthorizes appropriations for FY2009-FY2012 for such grants.

(Sec. 4) Reauthorizes appropriations for FY2008-FY2012 for grants for expanded delivery of health care services in rural areas, for the planning and implementation of integrated health care networks in rural areas, and for the planning and implementation of small health care provider quality improvement activities.

(Sec. 5) Reauthorizes appropriations for grants to help states develop and implement innovative programs to address the dental workforce needs of designated dental health professional shortage areas.

(Sec. 6) Requires the Secretary, acting through the Administrator, to: (1) provide guidance and technical assistance to health centers, state and local health departments, and emergency managers to integrate health centers into state and local emergency response plans and to better meet the primary care needs of populations served by health centers during public health emergencies; and (2) encourage employees at health centers to participate in emergency medical response programs.

(Sec. 7) Amends title XVIII (Medicare) of the Social Security Act to revise the definition of "rural health clinics" to extend from three years to four years the time frame for making certain designations related to a shortage of health services in an area.