Apple also has published a Q&A explaining what the transition means to MobileMe subscribers and how the company plans to go about it. Additionally, a notice at www.me.com/upgrade says that "you'll be able to upgrade your account to iCloud soon".
With that in mind, you may want to prepare your migration ahead of the Apple-imposed June 30, 2012 cut-off time when the MobilMe service will no longer be available. The support document KBHT4597 reads:
Effective June 6, 2011, if you had an active MobileMe account, your service has been automatically extended through June 30, 2012, at no additional charge. After this, the MobileMe service will no longer be available.
Following the transition, all your MobileMe mail, contacts and calendars will be moved to iCloud and you will retain your me.com or mac.com email address, Apple promises. MobileMe Family Packs and storage upgrades will cease to exist after today. Additionally, you can no longer create a new MobileMe account or start a two-month trial after June 6, 2011. People with unused activation codes obtained with a MobileMe box purchase can submit a refund request here.
No worry's, here's a leaked document to help you out: