Private Mortgage Insurance: This site of the private mortgage insurer provides excellent articles on how private mortgage insurance works. http://www.mgic.com/ See, especially, articles on entitled "Understanding Private Mortgage Insurance" and "Mortgage Insurance 101." http://www.mgic.com/home/articles.html    

Fannie Mae: The site of the nation's largest government sponsored mortgage enterprise. The site provides information about the firm's single and multi-family programs, financial information, homebuyer information, historical mortgage rates, and much more. http://www.fanniemae.com/    

Freddie Mac: The site of this government sponsored mortgage enterprise provides information about lender program, homebuyer information, an online version of Secondary Mortgage Market, corporate news and speeches, and investor data. http://www.freddiemac.com   

Government National Mortgage Association: The site of this office of the U.S. Department of Housing and Urban Development which guarantees mortgage securities provides information on its programs, investor news, and contractor information. http://www.ginniemae.gov    

Mortgage rates and calculator: The site of HSH Associates provides mortgage rate surveys and much more. http://www.hsh.com