Microsoft SyncToy
Well it's about time! Microsoft has finally released a tool for synchronizing folders between computers. This can be used to keep folders on a laptop and a desktop in sync. It's an unsupported PowerToy at this point, but it could well be functionality to be merged into Longhorn/Vista if it's well-received. It's definitely a product that has been needed for awhile. I used Groove for file sync and I just hated it. Groove was a pretty industrial strength network application and overkill for most people (not to mention absolutely horrible resource utilization). I don't know how well SyncToy works over networks, but it looks like it requires the computer running it to have access to both folders (through mapped drives or UNC paths). It supports one-way, two-way and other sub-modes of synchronization and looks promising. I'll be giving it a try so I can manage my laptop and desktop files better.
Check out the new tool here.