Steve Heller (the autor of C++: A Dialog, Optimizing C++ and many other great books) announces the release of UltraDedup http://www.ultradedup.com.
UltraDedup is a command line program created to ease the storage of backup files of VMWare virtual machine files by compressing and/or removing duplicate data.
A command line example that will create a Chapter (= a collection of files) in an Archive and place two files in it:
ultradedup p "f:\MyArchives\VHD_Miller.ud"
–n "Some chapter name"