Here's Go-Jeep's writeup on the rear main. It's not hard, but you do have to be careful and precise about how you reinstall your new seal.

http://go.jeep-xj.info/HowtoRearMain.htm

Unfortunately I don't have any info on the front main, and I want to get at mine while I'm doing my rear main/oil pan gasket on this 4.0. So I'll be watchin this thread for any good info...

How hard is the oil filter adapter o-rings to replace? I think that's where mine is leaking at.

On mine I had to remove the engine mount bolt on the passenger side so that I could jack up the motor with a block of wood under the oil pan in order to get the socket on the T-60 tork bolt because the frame rail was in the way and then it required a breaker bar & pipe extension to get the leverage needed to break the bolt free. Reassembly was easy.