RE: Bass/Catfish
Hogkiller, I'd check my state-regulations on that one. I don't know of anywhere you can bowfish for bass. I know it's illegal here in Illinois. Catfish is legal in some states. Your local DNR would be able to answer that for you.
Steve, it's not hard, but like anything else, when you first start out it's alot to learn/remember. Mostly, it's hand-eye-coordination. Get you a bow, set it up, and go out and shoot. Watch where your arrows go and adjust your aim accordingly. Remember that water refracts light, so you'll want to shoot lower than where you think you're seeing the fish.
The very first time I went, me and another guy who had never tried it before had our first fish in about an hour/ 30 shots.