Lenders are not going to just write down the balances on the loans (i.e debt forigiveness). It would be way too complicated and what happens when/if the owner manages to retain the property and sell if for a gain down the road?
What they might do (and I think are doing) is trying to find a way to restructure the debt to get the payment to something that the homeowner can manage. The majority of subprime loans were written as 2 year fixed with automatic conversion to 6 month Libor ARM.
Libor has dropped from ~ 4.5% in January to ~ 3% in February so all the lenders have to do is give the borrower a reasonable margin over Libor (say ~ 2.25 to 2.50%) and the borrowers will have a rate in the mid 5% range. Maybe the lenders will offer to freeze this rate for 2-5 years.
Most subprime loans have margins @ 3.5%+++ so just lower the margin will help and the reduction of rates at the short end of the yield curve helps too.
I don't expect to see debt forgiveness from lenders unless the specific property is sold in a short sale.