Music of Ghajini is directed by the one and only A. R. Rehman. Absolutely great music. I was kinda disappointed with Yuvraa's music, but this one is great. I specially Behka and Ghajini and Kaise Mujhe and .... actually I love all of 'em. But the best has to be Kaise Mujhe, I'm listening to it right now and it's intoxicating!
By the way these songs are in MP3 format, they're a lot bigger than .rm files.