Allows a state that does not participate in the Streamlined Sales and Use Tax Agreement (non-member state) to collect and remit sales taxes if such state adopts and implements the minimum simplification requirements of this Act. Provides that such taxing authority shall commence no sooner than six months after such state:

• enacts legislation to specify the tax or taxes to which the simplification requirements apply;
• specifies the products and services otherwise subject to such taxes that would be exempt;
• implements minimum simplification requirements, including providing a single entity within the state responsible for all state and local sales and use tax administration, a single audit and tax return for all state and local jurisdictions, and a uniform sales and use tax base for all state and local taxing jurisdictions;
• adopts a uniform rule for sourcing all remote sales;
• provides information indicating the taxability of products and services and exemptions from tax;
• provides free software for remote sellers that calculates sales and use taxes, files tax returns, and updates tax rate changes;
• exempts remote sellers and certified software providers from liability for incorrect collection, remittance, or noncollection of sales and use taxes; and
• provides remote sellers and certified software providers with 90 days' notice of tax rate changes.

(Sec. 3) Declares that nothing in this Act shall be construed to:

• subject a seller or any other person to franchise, income, occupation, or any other type of taxes, other than sales taxes, affect the application of such taxes, or enlarge or reduce state authority to impose such taxes;
• create any nexus or alter the standards for determining nexus between a person and a state or locality;
• deny the ability of a remote seller to deploy and utilize a certified software provider of the seller's choice;
• permit or prohibit a state from licensing or regulating any person, requiring any person to qualify to transact intrastate business, subjecting any person to state or local taxes not related to the sale of products or services, or exercising authority over matters of interstate commerce;
• encourage a state to impose sales and use taxes on any products or services not subject to taxation prior to the enactment of this Act; and
• alter or preempt the Mobile Telecommunications Sourcing Act.

(Sec. 4) Sets forth definitions used in this Act, including defining "remote sale" to mean the sale of goods or services into a state in which the seller would not legally be required to pay, collect, or remit state or local sales and use taxes unless provided by this Act. Sets forth rules for determining the source of a remote sale (i.e., the location where the product or service sold is received by the purchaser).

(Sec. 6) Declares that nothing in this Act shall be construed to preempt or limit any power exercised or to be exercised by a state or local jurisdiction or under federal law.