There was a new law enacted by President Bush in Dec that will affect whether you owe money or not. Is it your primary residence? Homestead?
On another note, why don't you get an agent and do a short sale rather than let the bank foreclose? This is much better on you for your credit nce it shows up as a sale, not a foreclosure. Also, most lenders are working with homeowners to do mortgage modifications if you want to stay in your home.
Have you tried one of the other two methods above with an experienced agent who can help you? If not, I would highly recommend that over foreclosure.