The Mortgage Bankers Association of America is the preeminent association representing the real estate finance industry. Their consumer information site contains several tools and guides to aid in purchasing or refinancing a home.
Freddie Mac is a publicly held corporation chartered by Congress to increase the supply of funds that mortgage lenders, such as commercial banks, mortgage bankers, savings institutions and credit unions, can make available to homebuyers and multifamily investors. This Freddie Mac site offers a step-by-step tutorial on the home buying decision process and the mortgage application process.
U. S. Department of Housing and Urban Development website provides extensive information about buying a home including affordability, borrower's rights, tips and tricks for shopping for a loan, and details about different home buying programs including FHA loan programs and other special programs.