Common at falls = yes.
Usually hit hard baits = no.
I caught one 10 years ago in a river on a crawdad crankbait, but haven't run across one since. I think they're opportunistic feeders, mostly vegetation/algae/scum/whatever - not predatory hunters. My guess would be that you snagged him with high-precision casting and bait control or you were fishing really slowly (and he was really hungry).
If you want to target them you can catch them on corn, McDonalds french fries, and white bread. If you use corn you can chum the area you are fishing for a few days before you fish and then just cast to the area you were chumming when you fish. Use really small hooks that will hold about 3 corn kernels and then cast out and wait. Certain places they can weigh over 50lbs. Carp fishing is growing in popularity and there are actually 6 or 7 major tournaments scheduled for 2008.