Rednroll

I purchased a Katzkin Leather seat kit. They're made specifically for the JK, and are available through the dealership accessories departments. I purchased my kit off of Ebay and installed it myself.

It's a complete reupholstery kit....so you completely remove the cloth seat covers and then re-skin with the leather kit.

Here's an install video of how it's done, to give you a better idea.
http://www.youtube.com/watch?v=hJ7CfLEeogc