Microsoft announced recently a new Sync Framework. This is a CTP release that is targeted for release in Q2 2008 and it supports P2P and Online/Offline synchronization of data. Currently though customers require Outlook like Offline/Online Sync scenario, it means developers doing custom coding. The Sync Framework is claimed to support P2P sync of any type of file including contacts, music, videos, images and settings. And has built-in support for synchronizing relational databases, NTFS/FAT file systems, Simple Sharing Extensions for RSS/ATOM, devices and web services.
I welcome having a standard framework for doing this repetitive job, it also removes the complexity of handling multiple connection types, scenarios, fail over, retry, etc. Download CTP from here.
Update Jan/2008: Read the design behind the Sync Framework from this blog post.