PlayNice allows you to Sync your crucial data between Macs and Windows on the same network or even in Parallels Desktop. Sync up to 3 Macs, 3 PCs, 2 Macs and a PC, a Mac and 2 PCs.
PlayNice will work with all configurations. In fact, it's a two-way sync, meaning it will perfectly merge your data on up to 3 different machines. Simply install the program on the machines you want to sync and you're all set. It's that simple. PlayNice syncs contacts, calendars and tasks between iCal and Address Book on the Mac and Outlook on Windows.