Internal Revenue Service
The IRS is the U.S. government agency responsible for tax collection and tax law enforcement. Contains downloadable forms, instructions, and agency publications. It also includes "The Digital Daily," an almost-humorous online newspaper. http://www.irs.gov/
Turbo Tax
Popular tax preparation software by Intuit. Integrates with Quicken, spreadsheets and offers state by state electronic filing. http://www.turbotax.com/