Rear View Mirror was created out of the need for a program to keep a real-time copy of a directory at a physically separate location. This way, if anything goes wrong with the physical drive where important user files are stored, up-to-date copies of all important files will be available on another media.
Rear View Mirror is an open-source project hosted on SourceForge.net. If you find bugs or would like to contribute, visit the SourceForge RearViewMirror Site or contact me.