I hope the links work:
http://www.studentuniverse.com
http://www.sta.com/

I played around a little bit with these 2 sites and a couple of itineraries, and compared the prices to what I was getting at Travelocity, and the prices in a few routes were better. I got a quote of around 1150 IAD-Delhi (which is around 350 less than a commercial website) and IAD-BRU gave me around 460. The rates were better for International flights but for national flights they were not. And in the front page of studentuniverse there are a couple of good deals. They might be useful for someone.