First, run, don't walk to a Barnes and Noble or indie bookstore or whatever and get the Carolyn Warren book :
"Mortgage Ripoffs and Money Savers."
It will tell you how to evaluate mortgage brokers -- I hand a copy to each of my clients now, and they love it.
author, "Diary of a Real Estate Rookie"
Insider Real Estate Tips with a Twist of Humor: http://tinyurl.com/2ag28z
When you've found the home and have a contract, then you can compare what you have with some of the other lenders to make sure the program is still the best solution. If you are comparing rates, make sure you make your phone calls at the same time and that you are comparing the same programs and the same terms. I hope this helps.