Unlike every other modern mouse, the Marble doesn't have any sort of scroll wheel… But fortunately this can be emulated in software. I've done this on my Mac using KeyRemap4MacBook and a custom private.xml. I've also been told that Marble Mouse Scroll Wheel (mirrored marbleinst.exe) works well on Windows.
: It has been replaced by, of all things, a wireless version. Why does a stationary mouse need to be wireless? I've got no idea. Maybe it's a conspiracy between Logitec and Duracell?