If you are syncing between different computers running the same Windows 8 app you can use the roaming settings and roaming folders
The sample covers both local and roaming data.
if you are trying to sync between an Wwindows 8 app and a iOS app you could use SkyDrive with the live SDK
from what I understand if you choose the roaming settings, windows will keep those settings up to date on each device, so that's what I would suggest. Hope it helps