Possibly one of NASA's most avant-garde projects ever, SYMPHONIES OF THE PLANETS is a five-CD set that is now out of print. Put simply, it consists of recordings made by Voyager 1 and Voyager 2 as they passed by the various planets and moons of our solar system. Although sound as we perceive it cannot travel in the vacuum of space, each planet and moon emits its own electromagnetic "signature" that can be picked up by the right instruments, and those emanations can be converted into sound and recorded onto compact discs for your listening enjoyment.
http://www.megaupload.com/?d=914MXYIE
(I haven't actually used that link, I downloaded the five volumes from different blogs all over the place - this has them all in one place though)