Even better than the rice is silica desiccant. Go to Michaels craft store and look in their flower arrangement section. Get help if you must, but ask them for the stuff used to dry out flowers for preservation.

You should be able to buy a 1lb bag for around $2.00. It's fine little balls of silica, probably too big to get in any cracks but you might want to put the ipod in some cheesecloth or something.

If you can open it of course, that's probably best but usually you can't. Make sure to remove the batteries at least, you don't want them leaking and ruining it for sure.