Red,
I get my leather from a local saddle maker.

You can get rubber (neoprene) sheets about 6"x6" in different thicknesses at the local Home Depot in the plumbing area. They make great vise jaw pads and are cheap too.

Red,
I have a vise that swivels in three degrees of freedom that I have glued 10 oz leather to the jaws. I use Barge Cement to do the gluing. I then trimmed the leather around the edges for a nice fit. I've used this set-up for 20 years making my knives and it works for all of my gun work also. If I have a nice stock I want to hold, or a blued barrel that I don't want to abrade, I use a towell to protect it as well. The leather is the same weight as I use for knife sheaths. I got it from Tandy.
Don

Thick saddle leather works well.

try looking at auto parts stores and/or sears. a tool company called lisle makes a set, and lisle is really common in auto parts stores, as they make cheap specialty tools. i can't remember the part number on the vice jaw pads, but i will give you a part number tommorrow, if i can find our lisle catalog at work.