V.S. Rawat's ISB-7.00 on which this site is based (from Ashish Thakkar's RMIM site). The Consolidated ISB site has about 3250 songs. Giitaayan appears to have started with ISB-7.00 and then added a bunch of songs of their own.
IndiaFM has a great collection too. Including recent songs. When you go there, look at the top right. There is a search bar. Choose "Songs" as the category and then search for songs that you are interested in. Very good collection.
Other Interesting ThingsNita Awatramani's Urdu Poetry website. Prakash's Ghalib's Ghazals.
Abhay Avachat's Aashi'yaana of Urdu Poetry. Abhay also wrote the famous A Sher A Day (ASAD) series (hosted by Nikhil Chowdhary). U.V. Ravindra had started a lovely ASAD blog but gave it up halfway. Still worth a visit.
Shatataarakaa a collection of Marathi song lyrics.
The rec.music.indian.misc newsgroup (a major force in the creation of the ISB).
If you can think of another site that should be linked here, let me know.