Attempting to do damage control, Apple is providing MobileMe status updates. The first status report is dated Friday, and states a further update for this weekend, and update about every two days.
The report includes details of the mail outage caused by a server blocking certain members, even permanently loosing email. Also, some details of the launch difficulties, and as guessed, Apple failed to anticipate the level of traffic. Increasing server capacity and fixing over 70 bugs likely contributed to more reliable operation a couple of days later.
The page has an RSS feed, which I recommend MobileMe members use as you can see when new posts are made.