There's this new program I've heard about that government is discussing where lenders would agree to forgive at least 10% for the underwater borrowers, including seconds just letting go of the debt. You should check that out too.
Faith Home Loans
If you're currently in a FHA loan, another option would be doing a Streamline w/o an appraisal. Your lender will only need to verify your current credit score and that you're still employed and earning an income. Exactly what you make, how long you've been employed, and what you having the bank will not be required. Given today rates, and depending on your taxes, your may also only need to bring one or 2 mortgage payments to the table just to cover establishing new escrows. Check with your lender to see if this is also available to you.
As long as the appraisal comes in at a point where the total loan to value (LTV) does not exceed 125% of the appraised value when the appraisal is done by the FHA appraiser, you should be fine.
You will obviously have to qualify under the general credit and income guidelines of the program, too.