its a disk juggler cd image, you burn it to cd like any other game. I'll explain what it does in greater depth. it like a vmu manager, its packed with tones and tones of tools.
-a vmu icon designer
-tool to change color of a vmu in dc frimware
-like 1000s of saves
-practically every vmu game ever made saved on the cd
-vmu emulator so you can play vmu games on the tv
-vmu defragmant tool
-tool to unlock 44 hidden blocks
-propbably a crap load of other stuff, but thats all i've used so far
-copy/cut/format/delete tools
might of game a bum link, sry that page didnt lead to the download but this one should
http://bswirl.kitsunet.org/vmutool/release/downloads/index.php?lg=en&menu=on