If you're wanting to buy a system instead of build your own, I recommend John at Custom EFIs
. The thing I like about his systems is they control the spark curve as well as fuel. Even if you decide to build one, it's a very good website to read for knowledge and has links to even more good sites.
I know other guys would recommend a Howell setup, and there's one or two who have completely built built their own systems! Like LEVE said, just do a search and you'll find writeups.
I've done quite a bit of tuning on my 304 EFI (from Custom EFIs). It's not perfect yet, but it runs so well that I don't mess with it all that often anymore. I'll be happy to share my tune with you if you decide you want to convert and get into burning your own chips, etc.
P.S. I decided to switch to EFI because I was tired of getting my butt kicked by carberators. No matter what I do, we just don't get along. I now have no cold start / running problems, no problems with stalling on hills, better gas mileage, and my horsepower is at least equal to what it was and I think is getting better as I tune. I've got my fuel pretty well setup now and I'm working on the spark curves.
I would definitely recommend fuel injection for anyone who hates carberators, or just likes being able to plug a laptop into your Jeep and see how it's running, then make changes to it with a few mouse clicks!