One problem I've always had with Google services was the difficulty synchronizing them with my desktop applications.
When I was using windows I managed to get a calendar sync using Rainlendar which also works on OS X although it doesn't give you 2way sync with iCal, and incidentally doesn't play that well with PathFinder's Desktop.
Anyway today I found a solution that works spectacularly on my Macbook, Spanning Sync which allows you to sychronise with your Gmail Apps or regular Gmail account, and will synchronize both Calendar and Contacts between iCal / Address Book and Gmail / Google Calendar.
If you find it useful you can use this code to get a $5 discount on the purchase price HAM46F, check it out now.