Whether you are trying to keep your home and stop foreclosure; pursuing a short sale as a means to avoid foreclosure; offering a deed in lieu so you can bail on an underwater mortgage and get on with your life and your financial future - you will find many resources on this website.
First you will want to determine if your home is worth keeping from a pure financial perspective. Next you will want to consider the different programs that have been created to help you modify your existing loan and get your monthly mortgage down to something affordable. There are loss mitigation documents to prepare for submission, free HUD housing counseling, government sponsored plans you may qualify for (HAMP, HARP 2.0), legal resources available. You can check out this online community where people have shared their experiences - what they have done, and are doing, to make and implement good choices about dealing with foreclosure