I was under the impression that Azam Ali identifies herself as an Iranian who grew up in India. Though either way, there are extensive ties to both cultures - and her music (with Vas and solo) incorporates many other influences as well. Anyway, her music is fairly distinctive, and I don't know if there's anyone really like her - but you might check out Lisa Gerrard, either solo or as half of Dead Can Dance. Aion may be a good match for Ali's Portals of Grace. The soundtracks may not be as representative of the sort of music you're after.) You can find many excerpts of the music at Amazon, iTunes, etc.
Jim is right, she is more than just Indian music. Her albums like Niyaz, Promise are closure to Indian music than ones like Children of Dune!
One Indian band trying in world music is Indian Ocean. As per Wikipedia some music critics describe the Indian Ocean music as "Indo-rock fusion with jazz-spiced rhythms that integrates shlokas, sufism, environmentalism, mythology and revolution". It has got a primitive sitewhere you can check some sample audio mp3 clips (video clips don't work). Kandisa is probably their best album so far.
If you want to listen to some songs of "Indian Ocean" try MusicIndiaOnline. Type "Indian Ocean" in the Search input and choose "Fusion" as the category. You will get some songs that you can listen to as streaming music. I found the volume a bit low for the few that I listened to.