The campus MyGatech service is based on the Zimbra Collaboration Suite which supports CALDAV compliant calender feature.  The Apple iCal application in OS X 10.5 (Leopard) is CALDAV compliant and works well with Zimbra.  Here is a link to instructions on how to configure iCal for MyGatech (this site requires that you login with your GT account and password to see the information within):

     http://share-it.gatech.edu/oit/ai/zimbra/faq/how-do-i-use-caldav-with-the-calendar-and-ical

Here is the Zimbra web site wiki page for using CALDAV with Leopard iCal:

     http://wiki.zimbra.com/index.php?title=CalDAV_with_Leopard_iCal