I moved to Colorado about a year ago, so I am finally learning how to catch trout in coldwater streams. But I started out as a fisherman in Missouri. I first fly fished for panfish - bluegill and sunfish. It's a great way to learn a little about fly fishing because I think they are easily fooled. I mainly used those popper flies with wooden heads and few feathers. They are easy to cast since they have a little weight to them. Generally you don't have to cast far because panfish often hang out close to shore anyway. If the bluegill won't hit the surface, you can really tie on just about any medium to small sized wet fly -- streamer or otherwise. I like wooly buggers. Let them sink some and them give them short jerking motions by stripping in your line.
Bass are extremely fun to catch on a fly. The main difference between fly fishing for bass and "regular" fishing for bass is the delivery method. There are large bass flies that can be worked like poppers, plugs, zara spooks, rubber worms, and jigs. Of course the flies look different, but the presentation is basically the same. But the great part about fly fishing is that you don't have to reel the fly all the way in. You can hit just the hot spots and then pick up your cast. Flies also land softer and avoid spooking the fish. A bass is also more likely to hold on longer to a soft fly than a hard plug. Ever have a bass strike a plug and spit it out before you have a chance to set the hook? I think flies also look more natural. In heavily fished areas, bass may get used to the typical lures but don't recognize flies as fakes.
I almost always fished from shore, but only because I did not own a boat. A boat is probably easier because it would allow you to cast towards the shore with plenty of room behind you for your backcast.
I usually use floating line. With an 8 to 10 foot leader you can usually get a wet fly down far enough. But on really hot or cold days, when the bass are hanging out on the bottom, you may consider a sinking tip line or partially sinking line. For bass I like to watch the line for a strike indicator, so I usually stay away from fully sinking lines.
As far as the catfish go, let me know if you figure out how to catch one on a fly! That would be awsome!