I'm searching for Halo 3 Credit theme and Halo CE Credit theme. Do you know if it's possible to find it?
I'm also searching for Halo 3 menu theme and Halo ODST menu theme ;)

Thanks in advance!

Seconding.

All of the Halo 3 credits music can be found on the soundtrack.. The menu music is also on the soundtrack, except for Halo 3 (monks) ad Cryo Tube.