With the upcoming release of
The Matrix: Revolutions, you'll be seeing (and hearing) that green Matrix code everywhere. For example, you can hear an MP3 sample from composer Don Davis'
Matrix Revolutions Soundtrack - the clip is from the track called
Neodämmerung. If you'd like to learn more about music in and around The Matrix, don't forget to check out the excellent
MatrixBeats website. And if you need to catch up before the final film's release, you can order
The Matrix Reloaded DVD. (Just remember to fast forward through the "rave scene".)
Back in The Matrix
The Matrix Reloaded (Widescreen Edition) 
Matrix Revolutions: Music From The Motion Picture 