Thank you Apple! I received my MobileMe Calendar Beta invite yesterday (after all other accounts in my mobileme family pack got it :-S).
I love the MobileMe service, but was always annoyed to see that you could not share a calendar for read/write access and sync it at the same time through MobileMe. So I was forced to use Google Calendar for this. Annoying, since I don't use google for anything else.
So in the past few years, I've mailed with some very friendly Apple support people, filing my complaints, I even sent a mail to Jobs (never got an answer though) about this. Lo and behold, a week after I sent my complaint email to Jobs, the Calendar Beta was introduced, with exactly the featureset I proposed in my many emails. I guess I wasn't the only one complaining then :-)
Yesterday, after upgrading my wife's iPhone to iOS4.0.1 I moved everything from google calendar to MobileMe. I hope to never have to look back again.