Rsync for Windows

http://stackoverflow.com/questions/528298/rsync-for-windows
http://stackoverflow.com/questions/106544/rsync-on-windows-socket-operation-on-non-socket

http://en.wikipedia.org/wiki/Rsync
http://en.wikipedia.org/wiki/Delta_encoding

SyncToy
http://www.microsoft.com/downloads/details.aspx?familyid=c26efa36-98e0-4ee9-a7c5-98d0592d8c52&displaylang=en

http://www.mydigitallife.info/2008/01/01/schedule-synctoy-to-run-and-automatically-and-repetitively/

http://www.terinea.co.uk/blog/2007/10/15/backup-tools-mirror-backups-and-microsoft-synctoy/