I don’t currently use Google Calendar, but that may change soon. Spanning Sync is a system pref pane that will allow true two-way synchronization of iCal, and Google Calendar. That means that changes made in either location will show up in both places. You can also specify which individual calendars get synced.
I say that it will provide two-way syncing, because Spanning Sync is currently unavailable. It’s in private beta. I’ll definitely be keeping an eye on the site for their public release. In the meantime, you can check out this video demo to see how it will work.
Currently I keep my Macs in sync via .Mac, but that doesn’t do me much good if I want to access my calendar from another machine. iCal does allow you to export your calendars to the web, but they are read only… you can’t make changes online. To me, that makes that feature almost useless. I really hope Apple is paying attention to this, and they are planning to do to iCal, what they recently did to .Mac mail… and give us a full featured online iCal equivalent.
found via TUAW