ICAL crashing Frequently - out of sync

[Harvey]

Recently I have having problems with iCal.

When I launch the application, ti gives me a warning that some items are out of sync, and asks whether or not I would like to verify them before launching ical. Normally this would be cool, but literally there are hundreds of items that need to be checked. This would take too long... Occasionally iCal will crash during this launch, I guess the load of checking all of the different un-synced calendar events is bogging down the application....

I there anyway that I can "clean up" both my PDA and ICAL calendar so that these warnings will go away, and things will run more smoothly?

Any advice appreciated.