E-tax Matters - Provides basic information on the filing of tax returns, with the opportunity to submit questions to the site's sponsors.
The Future of State Taxation - Book available from the Urban Institute.
Progressive and Regressive Taxes Explained - Essay discussing the concepts of progressivity in taxation, the role of taxation in regulating the economy, and explaining why sales taxes are considered to be regressive.
TaxPolicy.com - Quiz to determine your stance on tax policy.