Internet Tax Nondiscrimination Act

Internet Tax Nondiscrimination Act - Amends the Internet Tax Freedom Act to prohibit a State or political subdivision from imposing: (1) taxes on Internet access; and (2) during the period beginning on October 1, 1998, and ending on December 31, 2006, multiple or discriminatory taxes on electronic commerce.

Expresses the sense of Congress that elements of a State law providing for a simplified sales and use tax system for remote sales should include, among other things: (1) a centralized, one-stop, multi-State registration system for sellers; (2) uniform definitions for goods or services that are included in the tax base; (3) uniform and simple rules for attributing transactions to particular taxing jurisdictions; (4) uniform procedures for the certification of software that sellers rely on to determine State and local use tax rates and taxability; and (5) uniform electronic filing and remittance methods.

Prohibits a State requiring a seller who lacks nexus with, or a tax obligation to, the State from collecting or remitting sales or use taxes on any sales in that State until Congress provides such authority to the States by a specified joint resolution.