Format for an iCal.ics file

I want to make an iCal file, exported from my office database, containing my daily schedule and upload this file to mobilme then to my iPhone. This looks like a text file that I can make from my database but it contains some elements that look unique, like

UID:473B169A-F897-47D1-BD57-917AE29953EC

The rest looks pretty straightforward. Where can I find a description of the file format?

Doug