Most owners manuals can be purchased online. However, if you cant find it online, you can usually order them through a dealership. I had the same problem (not with a jeep) but I talked to the parts manager and they were able to order me one.
To the best of my knowledge there is no place to download an original equipment owner's manual. Aftermarket repair books will provide better information than the owner's manual but you'll have to buy...
You might try a junk yard, really. We have some in our area that actually sell things like that in their front shop; also, you can order one from Jeep through a dealer; that is how I got mine for my...