That method allows iCal to read Google calendars, but
it is just a one way, read only transfer.
If you want to sync information from iCal to Google,
you'll need Spanning Sync. It is a preference pane
that is designed to make iCal and Google work
together. As far as I know, it is the only product
of this type.
Doc
I have used Spanning Sync, and it's pretty cool. I did notice that it tends to create duplicate entries on Google Calendar every time it syncs. I have had to go back and delete two or more duplicate entries after syncing. And of course, those double entries appear in iCal, which are then synced to Google Calendar.
I haven't updated Spanning Sync for a while. Newer versions might have addressed this issue.
