I can no longer make the payments on my first and second mortgage, what should I do?

You don't foreclose on your home--that is something your lenders will do when you don't make payments. Note that when they foreclose, they will get possession of your home and can sell it; however, if it brings less in the foreclosure sale than the balance remaining on the loans, they can still come after you for the difference between what you owe and what the house goes for.

You might want to consider bankruptcy as an option, since it will get you out from under the debts, though you will likely still lose the home. Bankruptcy will hurt your credit rating, of course, but so will defaulting and foreclosure, and bankruptcy will protect you from additonal debts or judgements. You should consult with a bankruptcy attorney, armed with all of your financial information, to see if that would be the best option for you.

Note that if you believe you could sell the home for a reasonable portion of what you owe, another option would be to talk to the bank(s) and see if they would accept a short sale, which would result in them accepting less than full payment as full satisfaction of the debt(s).