Internet Taxation and the States
   Argues that a U.S. federal "moratorium" on Internet commerce taxes would erode state and local revenues and shift burdens to lower-income households.
   http://www.cbpp.org/512webtax.htm

Vertex Tax Cybrary
   Overview of U.S. state and local taxes implications of a company's e-commerce business.
   http://www.vertexinc.com/TaxCybrary/