MacBook :: Slight Clicking Sounds Coming From Side

I bought this computer (Macbook Aluminum 2.4 GHz - currently running Snow Leopard) last October - my warranty ends Oct. 16th. Anyways, I put a disc in the drive earlier today, and the computer took it right away. That was unusual because half the time it doesn't wanna take the disc (someone at the genius bar assured me all of these Aluminum Macbooks are this way). So continuing with my story, I took the disc out when I was done and I heard slight clicking noises coming from the side where you put discs in. I closed the computer because I thought it would stop it, reopened it, and it was still doing it. So then I restarted it, and I didn't hear it. Now I'm hearing it every so often.