It could be a number of things, sometimes that light comes on when the oil is low or needs to be changed, it also could come on if you have reached a certain mileage when service is supposed to happen, like the changing of your timing belt. Check your fluids first, make sure there is oil and water. If so you might have to call a mechanic to find out what is going on
This was Fords attempt to maintain their engine. So it could be anything from low coolant to low engine oil. As an option Ford also used this light to simply remind you to change your oil and filter at their recommended intervals. I'd contact a ford dealership and speak with someone in the garage, the mechanics would know. ;)
Try contacting a local garage to see if anyone has an OBDI reader (that's OBD One, not OBD Two). Anyone with such a reader should be able to bring up the code for you, and tell you what it means. If they can't tell you what it means, simply Google or Bing "OBDI codes" and you can find the one diagnosed on any one of a number of sites. Good luck!