The i-XPS SoundBox from Hercules is a splash-proof SoundCase that acts as a speaker thanks to the integrated NXT speaker technology. This case is compatible with all MP3 players and iPods due to the utilization of a 3.5mm connector.
Sad news is that it is a mono set up but its powered by two AAA batteries. Well alteast you can share your music with your nearby friends. More sad news, this is only available in the UK. Sorry.