Before a pap, you should wait 24-48 hours. I do not think it is the same at all for the LEEP. You are talking about the Saturday before, right? Since they take tissue and not just a swab, I don't think it matters if you have had sex a day or two before. The tissue goes into a solution and they actually examine the whole sample. It should be easy to tell blood and semen and other things from cervical cells when you have the whole thing. My doc never mentioned sex before the LEEP, but I am not sexually active. But, remember, this is not a good time to get pregnant so use extra protection.
You know, it wouldn't hurt to call the doc's office and ask to be sure.
Good luck with your procedure. Is it this Monday? I sure hope your fiance will be sticking around to pamper you. If not, he can at least help your prepare yourself - cook a few extra things, rent some movies, etc.