an RE expert's take:

"I would advise them to talk to their lender about restructuring the loan for a lower payment, lower interest rate and longer maturity. If that does not work, they could try a short sale if lender agrees to forgo the remaining balance. But since lenders have so many foreclosed homes they may not agree to absorbing more losses. In the long run, they would be better off if the hu*****and gets lucky and finds a new job before they go into default. Ruining their credit is not a good option since it will haunt them for many years. How about taking in a boarder for a year to help out on the payments until the hu*****and gets reemployed? Definitely continue to pay the mortgage until they come up with a real plan. Otherwise they are putting a gun to their own heads and it will likely lead to foreclosure and total financial disaster. Real estate prices will recover so they most likely only need to make it work for 2 years before they will no longer be under water."