iCloud email / Thunderbird
The problem here may be rooted in what everyone else is seeing, but I thought I'd add this post as I'm using Thunderbird and not Mail.
I did the MobileMe -> iCloud move a few days ago. Starting yesterday or today, whenever I try to access my iCloud email with Thunderbird (6.0.2) via IMAP, I get a pop-up message that says
Alert from account iCloud: Moved: http://me.com/move
When I click on the OK in the pop-up, I get a second pop-up:
Login to server mail.me.com failed.
I then have the option to enter a new password, cancel, or retry. It will loop endlessly like this unless I cancel.
It seemed to work right after the move and still works periodically. I am able to see my email with no problems via IOS 5 and on the iCloud web site.