The subject pretty much sums it up.
I moved to iCloud to save my e-mail address. Have desktop and laptop both running OS10.7.4 with no problems on iCloud. Also have iPhone 3 that is fetching e-mail just fine.
Will iPhone e-mail change when MobileMe is shut down after June 30th? I don't need any of the other functions of iCloud, just e-mail. Just want to keep my e-mail address of many years and receive e-mail on the older iPhone.
If you have already migrated to iCloud, then you'll have nothing further to do and everything will continue to work the way it is working now after June 30, 2012.