Listen.com
Search for as many as 300,000 artists and the songs they have ever sung in their lifetime.

India FM's Audio Channel
Check this one out, it has got an archieve of all Hindi songs from the past 3 years and some good English songs in RealAudio format.

BollyMP3.com
As the name indicates, a huge collection of Indian Music MP3 files. Also featured are a lot of Music Reviews.

Saregama.com
Online shopping mall for buying cassettes and CDs. Also features old and regional records.

Search MP3s - Western and Indian - Click Here !

More :
AudioFind.com
Bollywoodmusic.com