Although there are plenty of music apps on Orkut such as iLike, My Music and Vaga-lume Music (which is huge in Brazil), most simply convert their website within Orkut, with a few others requiring you to create an account with their main site (which is an extra hassle if you ask me).
One site called Sunoh.fm has launched an Orkut app that not only plays your favorite Bollywood music (most who seem to be independent), but also presents your play lists minus the clutter that is becoming increasingly common with many Orkut apps (at least as far as music goes).
According to their press release, Sunoh.fm has integrated very heavily within Orkut, which means if you favorite an album (or song) within Sunoh.fm, your friends will be able to check out your favorite songs on your Orkut profile (as long as they have installed the Sunoh.fm).
Besides the user friendly layout, one thing I really enjoyed was the ability to listen to a song without having to watch a YouTube video (which can often disappear due to copyright claims).
While I enjoyed using the Orkut app in general, I did find the Sunoh.fm to be "slightly buggy" as a few songs did not work at all (at least in Google Chrome, Firefox and Opera--I'm avoiding IE as it's tooo sloow for me).
I was also disappointed over the fact that you can not purchase most of the songs that you hear on Sunoh.fm.
According to my scrap conversations with Vivek, this may be due to the fact that many of the songs are from independent artists from India and are not listed on either iTunes or Amazon (which means ordering albums/tracks is currently not available).
Hopefully Sunoh.fm finds a way to resolve the latter issue (perhaps by teaming up with Google Checkout or TuneCore) as it would allow them to easily position themselves as the iTunes of Orkut (with a Bollywood twist of course).