Nice Q&A today from Apple regarding the changes happening as MobileMe transitions to iCloud. Mail, Contacts, Calendars, Bookmarks, Find My iPhone, & Back to My Mac make the cut. iWeb publishing, Gallery, and iDisk don't.
Some of the features on the way out are either being replaced or enhanced through some new features: iTunes in the Cloud, Photo Stream, Documents in the Cloud, Automatic downloads and purchase history for apps and books, & Backup and restore.
Another thing making the cut that a lot of folks were unsure about is web access for Mail, Contacts, Calendars, & Find My iPhone. I'm glad to hear that because I do use that access about once or twice a month. Instead of going to me.com for this access you'll go to iCloud.com.
Also on the chopping block are some things that honestly never worked all that well going between one Mac to another: Syncing of Mac Dashboard widgets, keychains, Dock items, and System Preferences.