The steam-cleaning thing can work if you get to it as soon as possible and often; it will still smell as it dries. We went from a hardwood floors house to wall-to-wall carpeting (not my choice!) and I thought we were going to have a real problem. We bought one of those quick steamer machines and it has worked really well whenever someone gets territorial or thinks the litter isn't just right. No smells and the carpet is clean. You might be able to rent a hand-held one which might work on your case, but it'd be iffy for getting all the spots.

Oh, and if follow the "final solution" offered by a couple of others, may the deceased come back and haunt you and seven generations after of your progeny.

kat