I haven't actually mounted it yet, but it comes with a very simple cradle which just clips around the 'ball' allowing you to swivel the sensor in any direction. They provide a single screw (+ gib fixing gizmo) for fixed mounting, or a small double-sided sticker. Will be surprised if the sticker is sufficient since it is only about 10mm diameter, but the sensor is very small and light so it might be ok.
I have it associated with my Aeon Labs USB Z-Stick and openHAB (www.openhab.org) is happily receiving temp/light/motion events. Very very impressed. More with the size to be honest, as there are other sensors out there (i.e. the MultiSensor from Aeon Labs) which do the same things, but this one is so small and discrete you could put it just about anywhere and hardly notice it was there.
There is a slick video from Fibaro here which shows off what you can do with a sensor like this, although I think some of these features would require the full Fibaro Home Center 2 controller in order to unlock their full potential.
Full details here...