The first thing you should look at when buying a used Jeep is getting a huge line of credit or a blank Visa card. You are gonna spend money like never before. The money may be spent making it dependable, or on future modifications, either way, it is expensive.
Second, if you like the Jeep, take it to a reputable shop and lay down the $50.00 or so for a proper inspection. If it passes, welcome to the wonderful world of Jeeping.
Jeeps are like helicopters, you wheel for 3 hours, repair it for 8 hours after. I know, bad analogy but its kinda true. Dont' be scared away, its still worth it.
Darren