OOHHHHHHHHHH YEAH!
Derek's post reminded me of something.
I one time got a bunch of gum all over my pants, and this weird-textured shirt, after sitting down somewhere I shouldn't have. Anyway, what I did to get it out, was used one of those cans of compressed air.
If you turn one of these cans of compressed air upside down and spray it, then this cold fog comes out. If you just *barely* squeeze the trigger though, you can get it to drip out of the little straw at the end of it. So I turned the can upside down, dripped the liquid onto the gum, and you can basically flake it right off, like Derek said. I didn't have luck with the ice thing, so this seemed like the next best idea. Dunno how it might affect the leather though... but it worked great on clothes.
And hey, if you turn it right side up and take a hit off of it, you can have a wicked buzz while you're cleaning your car!

j/k