One of the best known (in the Linux world) incremental backup program is rysnc http://rsync.samba.org/. It is used extensively to synchronize mirrors of files etc . It is explained at http://rsync.samba.org/how-rsync-works.html.

I use it on a Windows PC to backup to a Linux server. It is a command line program, not a GUI but when setup works very effectively.

Chris

It is still working for me- for version 6

After much testing and looking for a suitable solution, particularly one that was free I chose Unison http://www.cis.upenn.edu/~bcpierce/unison/. It was a bit fiddly to set up, but I have it synchronising my documents and favorites at home and at work. It only moves the parts of a file that has changed and not the whole file. This is based on rsync.

Chris
Adelaide
Australia