Internal Revenue Service The Internal Revenue website provides ready-to-print forms and instructions, as well as providing the portal to online tax filing.
California Franchise Tax Board California income tax forms and instructions are available here in ready-to-print, fill-out-and-print, and electronic filing options.
Nolo's Tax Center The leading legal self-help publisher, Nolo Press, has a Tax Center where you can get information on business tax, personal income tax, deductions and audits.
United States Tax Court The US Tax Court has a website filled with information for people who find themselves in court for tax-related matters. Included is a link to the very helpful taxpayer information page at: http://www.ustaxcourt.gov/taxpayer_info_intro.htm
Uncle Fed's Tax*Board Uncle Fed is a website dedicated to providing information and resources for taxpayers.
Taxes on Yahoo! Personal Finance The Yahoo! Finance team has put together articles, calculators, tools, & advice on many tax topics.
Tax Guides from TurboTax One of the leading online tax preparation systems, TurboTax has a website with free tax calculators, estimators, guides and help.
Tax Resources Directory This huge directory of tax resources is maintained by an individual. He says that it is "made available as a public service. Its purpose is to provide a gateway to tax resources available on the World Wide Web."