Windows only: NasBackup is an easy to use interface for the powerful rsync backup utility.
You can use NasBackup right out of the box and easily schedule backups from your machine to another machine on your network. Underneath the GUI is still all the power of rsync, if you're familiar with rsync commands you can edit the main.phase file in the NasBackup directory to including any rsync tweaks you like. Even if you never get under the hood and mess around however, NasBackup is quite capable. Once you select the data you want backed up, the destination on the remote computer, and tell NasBackup how frequently to back the data up, from there out it works in the background incrementally backing up your data to the remote disk. If you're interested in shopping around for a backup solution, make sure to check out our previous Hive Five on best backup tools. NasBackup is open source, Windows only. Thanks Mike!