Thanks for your replies. They are very helpful. I don't have a grease gun, but I can buy one. Can I drive to an alignment with out greasing it up then have them grease it there? Does AdvancedAutoParts Sell thos TRE separators or ball joint separators?
Any shop claiming to be an auto parts shop will have them. ANY shop.
And while you're there buy some jack stands. Really. Never work under a vehicle only on a jack (and never use crap like cinder blocks!) 3 1/2 ton ones will be plenty enough to start with (you could get away with 2 1/2 ton ones, but they will be a little short for everything) and should be good enough for most jobs. If you have more money, buy 6 ton stands, but honestly, I doubt you'll need them for a long time, and you'd need to buy a jack that can jack high enough to get the extra height out of them.
I suppose you could get someone else to grease it for you, but the labour will cost more than the gun and the grease (They'd probably charge you the price of an oil change, since really nice shops will grease the chassis when they do an oil change). The greasing is the really easy part, so if you're going to do this yourself, why give them the gravy job?
If you buy the parts from RockAuto, and you buy the tools on the cheap (Habor Freight or something similar in your area?), this job is going to cost you $200 or so. Compare that to a shop where they're probably going to charge you at least $100 per TRE (parts included), maybe more (I know in Canada you'd not find a shop that'd do the work for under $150 parts included, more like $200, but parts are priced something crazy here).
A little suggestion, since you've not jacked up the Jeep--I found on mine that the frame would bend if I rested it directly on the jack stands. Not good. So I put a small bit of scrap 2x4 between the stand and the frame. No more bending! Held up just fine.