If you haven't heard (which would be really weird), Bungie will be releasing a soundtrack on the same day and date of Halo 3 ODST. The release date is (say it with me) September 22 2009; which is taking too long to get here. Check out the partial tracks from the soundtrack below:

ODST Theme (Partial) - MP3 [3.5MB]
Rain (Partial) - MP3 [2.9MB]
Traffic Jam (Partial) - MP3 [4.8MB]
Neon Night (Partial) - MP3 [3.5MB]