Recently Microsoft bought foldershare. The assumed goal is to bulk up the folder sharing capabilities of the upcoming Live Messenger. They have now decided to make FolderShare free.
I finally got around to playing with this. I installed it on two mobile computers and my home server. Now I have a directory that I can keep synced between all 3 no matter where I am. So far so good. One word of caution however. If you leave it running on a laptop for example, it will probably pull your battery down as it seems to continuously poll the HD for changes.