What is the best way to set up a shared calendar in iCal? I am looking to have a shared calendar which my partner and I can access.  I have a MobileMe account and my partner has a Google account.  We both have Macs, I have an iPhone and she has a Blackberry.

I am looking for a solution where we can create a calendar that we both have access to from iCal (and maybe iPhone / Blackberry if possible) and that we can both edit.

So far however, I have not managed to get anything to work.  The logical solution seemed to be to create a Google Calendar on my partner's account and subscribe to it on my MobileMe account but I cant get any changes I make to be pushed back to the Google calendar.
Make a Google Calendar, and sync it to iCal.
Directions are in this Google article.