Well, if you're running Windows XP Professional at home, it *might* be possible to sync via the Remote Desktop Protocol, but it's a long shot.
There's documentation for syncing Palms and Pocket PC's over Citrix MetaFrame's ICA protocol, (which runs on top of Windows Terminal Server, which is similar to--but not the same as--using Remote Desktop to "phone home"), but there doesn't seem to be any documentation for syncing over RDP (remote desktop protocol). Cynthetiq's suggestion of backing up the device to some kind of removable media would probably be a lot easier.
Do you just want to back up your data while on the road, or do you really want to sync with the PC at home? I'm just curious, how much info is going to change while you're away from that machine...
--edit--
check out this
http://tinyurl.com/5wvnb ActiveSync over a VPN, very cool stuff