The Tax Resource Group
Tax Research, consulting and research for attorneys, CPAs and EAs.
http://www.taxresourcegroup.com

Uncle Fed's Tax Board
Providing information on the United States tax system, filing a tax return, and problems that may be encountered by taxpayers. Also offers links to downloadable tax forms.
http://www.unclefed.com

TaxLaw.be
Links and information concerning Belgian and international tax law.
http://www.taxlaw.be/

Tax Facts Center
Tax information for citizens, policy analysts, legislators, and the press. A joint project of the Urban Institute and Brookings Institution.
http://www.taxfactscenter.org

Inc.com
Information and resources on law and taxation for small businesses and entrepreneurs.
http://www.inc.com/guides/legal/

Boon Docks, Inc.
Compilation of US withholding and unemployment tax rates.
http://www.tax-tables.com/

IRS
The U.S. government agency responsible for tax collection and tax law enforcement. Includes income tax forms, instructions, and agency publications.
http://www.irs.gov/

Australian Taxation Office
Tax information for individuals, Companies and organisations, from the Tax Department of the Australian Federal Government.
http://ato.gov.au/

IRS Audit Infrormation
How to prepare, what to expect, the different types of audits, and taxpayers’ rights during an audit.
http://www.irs-audit.net/

Phoenix
Consultancy offering articles on a variety of tax subjects.
http://www.phoenixwm.com/

AskTaxGuru
Forum for discussion of tax issues.
http://www.asktaxguru.com