How to mount a flat panel TV on wall?

They look great in any room, save space, and what better way to watch sports or any other HD programming at home? Chances are, if you haven't already purchased a plasma or LCD TV you're most likely thinking about putting one on the wall in the living room or above the fireplace in the family room in the near future. The only problem is, you either have to be handy with a stud finder, drill, and Sheetrock saw or need to have the TV professionally installed. Feel free to post your questions or comments on this subject.