Below are some links to website you may also find useful.

Federal Tax Information
Internal Revenue Service - http://www.irs.gov
Depeartment of Treasure - http://www.ustreas.gov
IRS Latest News - http://www.irs.gov/newsroom/index.html
IRS Forms & Publications - http://www.irs.gov/formspubs/

IRS Tax  Information for Businesses - http://www.irs.ustreas.gov/businesses/
IRS Tax Information for Individuals - http://www.irs.ustreas.gov/individuals/

Michigan State Tax Information
Michigan Taxes: Department of Treasury - http://www.michigan.gov/taxes/
Michigan Tax Changes: Department of Treasury - http://www.michigan.gov/taxes/
Michigan Business Tax - http://www.michigan.gov/mbt

Tax Code
Tax Code Online @ Cornell University - http://www.law.cornell.edu/uscode

Government and Corporate Information
U.S. Government Accountability Office - http://www.gao.gov
SEC Database of Corporate Information - http://www.sec.gov/edgar/searchedgar/webusers.htm

Tax News and Information
Yahoo! Tax News - http://news.yahoo.com/fc/us/taxes_and_the_irs
MSN Money - Taxes: Tax Planning Tools and advice - http://articles.moneycentral.msn.com/taxes/home.aspx
Forbes: Legal and Tax News and Information for Entrepreneurs and Small Businesses: http://www.forbes.com/entrepreneurs/lawtaxation/