There's no way to track it. The only good that will come of the situation is that the person will not be able to setup an iTunes account withit because it's registered to you. However, if they know anything about computers, then they also know that you don't need iTunes to add music. Basically, you're screwed.

Reminds me of a time in my past life. I had stole a CD player and other stuff from this kid. Somebody ratted me out and the police came to ask questions. I got scared b/c they said they were going to search the house so I took everything to school and put it in this cabinent in a classroom. Came back the following week and all my booty had been boosted. No honer amongst thieves...