The check engine light could mean anything. It could be something as little as not having your gas cap tight to something major under the hood. Everything in this car is tied to the computer.
Take the car to a auto parts store. Most of them will check the codes for free. Come back here and at the top of this section is a thread titled DTC Codes. Look in there to find your code and it will tell you what it is. If you have troubles finding it, just post what the code here and we'll tell you what it is.
If you car is running fine though, I wouldn't worry to much about it. Probably something easy.