My xbox 360 is overheating? and shutting down. What's wrong?

My 360 keeps overheating and manually shutting down. It displays the 2 red lights like it's suppose to and the fan spins really fast... At first I thought it was something to do with the console itself, but after reading about another persons problem with heating, I noticed that his xbox started acting up on Jan 19th 2010, the same day mine did,and even though mine is older then his I don't believe it's a coincidence... So my question is if anyone is having this problem and is there any simple fixes or should I send it to Microsoft?