Do you even need to recalibrate the throttle? On my old 4.0 it took about two minutes to get off, two minutes to clean, and two minutes to reinstall. Biggest pain was going to buy the gasket from AZ.
Lee, I suggest that you join a Jeep forum that has a DIY section. Everything you went to get done at the dealer, you could have done yourself and saved a couple of hundred dollars. Just save all reciepts for warranty purposes. This forum is all about changing your own oil, air filter, and Lord knows everything else under the sun.
Even though I consider myself mechanically inclined, if there's something I need done that I never had to do before, I come here first. I guarantee everything you'll ever want to do, someone else here has already done it and can walk you through it. Also, youtube is a good source for DIY vids and how-to walkthroughs.
Your throttle body COULD have been carboned up, but in all likelyhood it wasn't. The "kit" that they charged you for contained nothing more than a three dollar gasket and O-ring. Run decent (name-brand) gas and you should never have to clean your throttle body. On cars that I buy new, I pull them after about 100k miles and they're usually lightly carboned, not enough to make a difference one way or another. Sometimes I don't even bother spraying them down with carb cleaner.
And Saturn_Fan, we've been spoiled with Richpin's videos for quite some time now, no?