I was able to get a mortgage modification on my first mortgage. I printed the forms online, filled them all out, and faxed them in. It took a few follow-up phone calls, answering some additional questions, and faxing some additional information. But they did modify the loan. They reduced the interest rate slightly and changed our payments to interest only for three years. At the end of the three years, our loan gets reamortized and the interest rate reinstated to the previous level. We are currently saving about $600 per month, but at the end of the three years, we will be paying about $100 per month more than we previously were. (I certainly hope that our financial situation improves by then!)
I also tried to get a modification on our second mortgage, and they said they couldn't do it. So I guess it depends a lot on the lender. But with the housing market the way it is right now, they lenders may be more willing to work with you because they really don't want to end up foreclosing on your house. In all likelihood, they won't be able to sell it without losing money.