Have you tried MS Backup?
You don't mention what O.S you are running but I am running XP pro on a laptop and desktop which are on a network.
I load up MS Backup (free with Windows) and run through the wizard specifying what files I want to back up, then it asks for a location.
I have a directory shared on my desktop called "backup". I simply specify this directory to back the files up to and it works fine.
You can also set a schedule for when the backups take place.