Below are the release notes of today’s iCloud mentioning about the migration from MobileMe to iCloud and other new features

Please file a report using the Apple Bug Reporter if you experience any bugs before or after moving.
Accounts
• If you get an error that your account is not eligible to move to iCloud, even though you have signed in to your MobileMe account on OS X Lion 10.7.2 Seed (Build 11C35) or later and/or iOS 5 beta 5 or later, perform the following troubleshooting steps:
1. Your email address may not be verified. Go to AppleID.apple.com > Manage your account > Sign in and verify your primary email address. You can also change your primary email address, and then verify the new address. Try to sign in to me.com/move again from your computer. If you still get an error, move on to 2. If you don’t have an iOS device, skip to 3.
2. Delete your MobileMe account on your iOS device, and then re-add your account. Try to sign in to me.com/move from your computer’s browser again.
3. Sign out of your MobileMe account on your OS X Lion Mac, and then sign back in to your account. Try to sign in to me.com/move again.
” Note: Inactive MobileMe accounts are not qualified to move.
• All iCloud features including Mail, Contacts, Calendars, and Bookmarks should be automatically set up on iCloud as you had them on MobileMe. Occasionally not all features are turned on after moving. Check your settings and confirm the services you want to use are switched on.
• Occasionally, accounts set up in iCal on a Mac (not through MobileMe System Preferences) will not get moved. To resolve this issue, remove your MobileMe account from iCal, and then add your iCloud account in OS X System Preferences > Mail, Contacts, Calendars.
• A secondary MobileMe account set up in Mail on a Mac (not through MobileMe System Preferences) will not be moved automatically. After moving to iCloud, remove your secondary MobileMe account from Mail. Then add your iCloud account in OS X System Preferences > Mail, Contacts, Calendars.
• If you don’t receive an alert on your device or computer to complete your move to iCloud, go to settings on each device and computer. Accessing settings will automatically start the move of your MobileMe account to iCloud and allow you to turn each iCloud service on or off.
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• If you have a Family Pack master account, you will lose the ability to create or delete family member accounts once you move to iCloud. You should complete any family member account management prior to moving.
Calendar
• If you never upgraded to the new MobileMe Calendar, make sure to turn Calendar off on your iOS devices or computers prior to moving and choose the option to keep data on your devices. This will prevent the loss of calendar data. You can confirm you have the new MobileMe Calendar by signing in to me.com/calendar. If you can see your calendar, you have upgraded to the new MobileMe Calendar and should ignore these steps. But if you see an error page, turn OFF Calendar on each device and computer:
? iPhone, iPad, and iPod touch: go to Settings > Mail, Contacts, Calendars > MobileMe. Turn off Calendars and choose the option to keep data on your device.
? Mac: go to System Preferences > MobileMe > Sync tab. Turn off Calendars and choose the option to keep data on your Mac.
? PC: go to Control Panel > Network and Internet > MobileMe > Sync tab. Turn off Calendars and choose the option to keep data on your PC.
Contacts
• Some contacts, as well as mailing addresses within some contacts, may be duplicated after moving to iCloud.
Find My iPhone
• Find My iPhone requires iOS 4.2 or later after moving to iCloud.
Windows
• Moving to iCloud on Windows requires that you open MobileMe Control Panel. After completing your move from the web, open the MobileMe Control Panel to complete your migration. If the MobileMe Control Panel was open when you performed your move, simply quit and relaunch it.

 
To download iCloud, check out our download links here.