Is there a way for Windows Home Server to keep one of its share folders sync'd with a folder on one of the computers on the network?
I use synctoy - there is another question regarding this here
According to this page: Windows Live Sync as a Service on Windows Home Server, Windows Live Sync should run fine, and would do what you want.
You'll need a Live account, and then you just set up a private folder and share it on the two machines, and they'll be kept in sync.
I use Unison. It's a pain to configure on Windows, but it's much much faster than any other syncing tool