Syncing Contacts and iCal between multiple Macs and iOS?
I've been extremely happy with iCloud syncing between MacBook Pro, iPhone, and iPad. Once set up it works flawlessly and reliably unlike MobileMe which I had for years and was useful but never totally trustworthy. iCloud really is a great solution for syncing address book and calendar and reminders. I'm also enjoying it's syncing of bookmarks and other safari browser data.

My only caveat about it is that some MobileMe users have had some issues in doing the move. None of these issues to my knowledge have been unsolveable but there have been some bumps. For users with an Apple ID and no legacy of MobileMe use it's extremely smooth to set up.

All iOS devices need to be running iOS 5, Macs need latest version of Lion.

http://www.apple.com/icloud/setup/