I found this while searching for an audio version of the Bhagavad Gita to listen to while i sleep or nap. The mp3s are at the bottom of the page, and consist of sung sanskrit passages of the gita, followed by spoken english translations of each passage -all set to lovely indian music.
Its quite wonderful, and i believe the 4 files contain the entire Gita. MP3 Downloads
p.s. The rest of the mantras are pretty good, too.