Many of today's high-end cell phones are powered by Microsoft's operating system, which meant that Mac users couldn't synchronize their contact information and other data. Now, the release of Mark/Space's  jumps over that hurdle. The new version ties into Apple's Sync Services under Mac OS X 10.4.7 or later for addresses, calendar items, and to-do lists, and it offers specific support for synchronizing data with Microsoft Entourage. It also includes plug-ins for iTunes and iPhoto to transfer music and photos to the phone, as well as the capability to mount the device on the Desktop for direct file transfer. A new toolbar in version 2.5 offers quick access to commands, including an easy way to install Windows Mobile software. The Missing Sync for Windows Mobile 2.5  for owners of version 2.0 or later, or as a $40 electronic download (or $50 CD) for new users. Upgrades from older versions or some other eligible products cost $20.