pardon. my usual posting is on the latin america and european boards, so didn't realize the Bermuda question was one of "those" touchy ones here.

There's some great snorkeling trips over shipwrecks. I don't think there's any you can swim out from shore to, but there's some reasonably priced boat trips that will get you there. Although geographically "wrong", Bermuda postings are with the Caribbean section on Fodors, btw, so you might find some specific recs there.