I would recommend going to your local mortgage broker (not a bank) who can shop the wholesale rates from banks all across the country. You need to be self educated as to what the rates are so u don't pad their pockets too much. the higher the rate they can sell you, the more commission they get on closing that loan. Also, be willing to wait out a mortgage for up to a couple of months if you want to lock in the best rates. Daily mortgage rates tend to move with the 10 year bond (look at this rate on finance.yahoo.com ) its on the left hand side. As people buy the bond, the rate drops, as people sell it, the rate goes higher. (typically if the stock market does bad the rates should drop in your favor) You can also research the mortgage rates off of the same page. Dont let the guy try to sell you on a higher rate. tell him this is what you want, this is what you see on yahoo etc etc. the reason i know all of this is because an acquaintance of mine is in this business and I have gotten 3 loans from him, 2 purchases and one refinance. I started out with lending tree, but you dont have a rep locally nearby to deal with, I like using a broker, because they handle all of the hassle and paperwork needed to secure a loan.
PS. get as much money into your bank accts as possible, and pay off as much outstanding debt as possible to help u secure the loan.