How can I check if an event exists in iCal

I know just enough AppleScript to copy and paste existing scripts into something I can use, I recently modified a script from http://www.macosxhints.com/article.php?story=20051230060736104 to create an iCal event for me (the script is triggered by a rule in Entourage).

I realize now that the script should first check that the event hasn’t already been created. But I don’t know where to begin.

Can someone help? Thank you.

I was able to get a workable solution using the “getTodaysiCalEvents.scpt” that comes with Growl.
http://growl.info/documentation/ical-script.php

Using the script I check to see if an event’s Summary is something I expect, and if it is then I set a flag so my script will NOT make another of the same events.