U.S. Congress - http://thomas.loc.gov/

IRS - http://www.irs.ustreas.gov

Federal courts:

• All Circuit Courts - http://www.findlaw.com/casecode/courts/index.html

• District Courts - http://www.uscourts.gov/allinks.html

State statutes/legislation

State Corporation Databases

State Tax Forms - http://www.irs.ustreas.gov/prod/forms_pubs/ftaframes.html

State case law - http://www.findlaw.com/casecode/state.html

State courts online -  http://www.ljextra.com/courthouse/statelinks.htm

Municipal codes:
Municipal Codes Online - http://www.spl.org/govpubs/municode.html
Municipal Codes Corp. - http://www.municode.com/database.html