to commonly asked questions.

Multiple backups with one drive in Time Machine

MobileMe Syncing seems to have been down a bit over the weekend. Many clients have reported syncing issues. Apple states they were running maintenance on the sync servers and all services have been restored but I don’t think that’s the case.

Apple - Support - MobileMe - System Status Recent History

Don’t trust this:
Apple - Support - MobileMe System Status

My advice, wait a few hours and maybe we’ll all be back online. In the meantime, manually force the sync from the menu bar icon.
This image is a theme.plist hack