I've been swimming while listening to my iPod - I put the iPod in a waterproof clear cell phone bag (used by canoests and kiyakers) with iTrip (fm transmitter for up to 2 meters) and I listen with a speedo mini waterproof fm radio (2 cm x 4cm with ear buds -- about 25 bucks). The iPod floats behind me and doesn't add much drag. I was worried it would need some air circulation but it doesn't overheat. At first I put it in a double water proof bag, but the bag seems pretty tough and I never got any water in it. Now I swim for an hour instead of half that...
