In late December Mortgage Forgiveness Debt Relief Act of 2007 came into existence which is meant to provide tax help for people who are selling their house in a short sale or are facing foreclosure.
Before this Act, if value of house declined & lender forgave any portion of your mortgage debt, according to tax code forgiven amount was treated as income and was taxable.
If it is your principal residence & not a investment property or second home then as per MFDR Act you can exclude up to $2 Million of mortgage loan debt forgiven in years 2007, 2008 or 2009. Additionally, this debt relief will be applicable for acquisition indebtedness only.