The perspective of having music on an amphibious MP3 player during my swimming routine was just too tempting, so I bought a SwiMP3 on my last trip to NY. They're boasting that it's working with PC or Mac, and well it should, because it is basically just a waterproof USB storage device with bone conduction sound transfer.
But unfortunately, it does not work with Mac OS X 10.3.6 for the time being. Technical support at Finis Inc. claims a OS X bug in USB handling responsible for the problem. So Mac users, do not buy the SwiMP3 just yet!