Currently Being ModeratedMay 23, 2012 8:20 AM (in response to Mike Strohmeyer)
You can migrate from MobileMe to iCloud at http://me.com/move even with Snow Leopard: when asked to confirm that your Mac is running Lion just lie and say 'yes'. Of course you won't be able to access iCloud directly from your Mac.
If you have MobileMe mail set up to collect mail from external POP accounts you should cancel this before migrating, or you may find it still working in iCloud (where it isn't supposed to) and with no way of stopping it.
This will be the situation with Snow Leopard when you have migrated:
•Your email, calendars, and 'Find my iPhone' will be migrated to iCloud. Contacts and Bookmarks cannot be migrated from a Snow Leopard Mac.
•Your iDisk, together with website hosting and Gallery, will continue to work as before until next June.
•Syncing of Dashboard Widgets, Dock Items and Keychains between Macs, and Mail Accounts, Mail Rules, System Preferences, Signatures & Smart •Mailboxes between Macs & iOS devices, will cease altogether.
•You will be able to access email and calendars on the iCloud website at http://icloud.com provided your browser is reasonably up-to-date.
•You will not be able to sync contacts or bookmarks from a pre-Lion Mac.
•You will be able to enter the server settings for email manually in the Mail application and access your email.
•You will not be able to sync your calendars directly.
•Some people have been able to set up calendar syncing by using the method detailed here - this is an unsupported hack and may not be reliable, and may stop working at some future point.
•Address Book won't sync: this page has a convoluted hack to make it sync which has been reported as working (and as not working by others). I've not tried it.
There are a couple of third-party solutions which may be of interest.
•BusyCal is an iCal-like calendar application with extra facilities: it can sync with the iCloud Calendar while running on Leopard, Snow Leopard or Lion. A single user licence (two machines allowed) is $49.99.
•Soho Organizer can sync Calendars and Contacts with iCloud on Leopard, Snow Leopard and Lion. A single user licence (multiple machines allowed) is $99.99.
(I have no connection with either firm.)