Just set it up; note that you have to hit m.google.com/sync from your iPhone Safari browser to pick which calendars to sync. Outbound works fine without it, but inbound sync doesn't do anything until you select calendars.
With BusySync keeping my iCal synced with Google, it takes about 4 seconds for my iPhone to update after I add an event to my iCal.
I had this through nuevasync.com which was pretty awesome. I want to support them as a startup but this is all they did, and so what if they did it 2 months ago, google now does it and I am far less worried about google disappearing than I am a tiny startup.
I hope they come up with something else it was an awesome product.
With BusySync keeping my iCal synced with Google, it takes about 4 seconds for my iPhone to update after I add an event to my iCal.