Tempeh is cultured soy beans. Most people find it easier to digest than tofu. It's made by soaking or cooking (dunno) soybeans and then adding a culture and keeping it warm until it looks like tempeh. It sometimes gets black spots but that doesn't mean it's gone bad, it just tastes stronger. When there's a lot of them you'll want to toss it. Try to buy fresh if possible--it tastes so much better than frozen. OMG, I had really fresh tempeh in Eugene once. It was fantastic.

Most people fry it a little. You can also cut it into chunks and put it in soup. vegancooking's memories section has lots of recipes, see if you can find tempeh in there.