Directory of Institutes, Organizations, and Clubs on Taxes and Taxation from Free-Market. The Tax Foundation is committed to a well-informed citizenry and simplicity and stability in tax policy. It is against retroactivity in tax laws, and supports neutrality in tax policies which do not hamper international trade. A new org that primarily focuses on economic policy issues, especially taxes. They also cover entitlements, monetary policy, and deregulation, and seek to bring the insights of Austrian economics to a wider policy audience.
Site looks pretty and is easily navigable.
Find extensive sections on budget reform, electricity deregulation, health care reform, the environment and trade policy. A non-profit association working for the common sense in taxation of personal savings and investments. An independent tax watchdog group. Conservative nonprofit organization devoted to low taxes and a limited government. NTU has consistently defended taxpayers for years.