Sounds like you have the Death Wobble...dun dun dun!
It could be a number of different front end items. Do a quick search in the box above and see what you can find. Let us know if you have further questions about DW and we'll be glad to help you out. I've had it on my 04 and it turned out to be the tires. They were MT/Rs nearing the end of their life.
Welcome to Jeepz!