A Mobile Me Updater is available that will replace your old .Mac (dot-mac) icon in System Preferences with the new Mobile Me. Download it here. The download is completely painless and should take no longer than two minutes to install on a moderately speedy internet connection.
After installing the updater, login to System Preferences and you should see the icon portrayed in the image above. Mobile Me should allow you to connect using your original .Mac user-name and password, although it will give you the error portrayed in the image below.
