It's essentially just the threaded part of a plastic bottle sized to fit by heating it up attached with a tie-wrap.
The tools I used:
a pipe wrench
a utility knife
and a iron saw
The materials used:
a plastic bottle
optionally some kind of rubber
Step 1: Cut the Top Part of the Bottle
Step 2: Saw Out a Section
Step 3: Slightly Melt the Plastic
Watch out for the fumes, they are not healthy.
Step 4: Fit and Attach
You can then attach the mount to your steering wheel using a zip-tie, this also makes the fit tighter so keep this in mind when tightening.
I put a rubber band between my steering wheel and the zip-tie to keep it from twisting around but I would recommend using a piece of bicycle innertube for this it looks a little sloppy like this.
Your done! You can now go and buy a cheap but bright flashlight (like the one I have: http://www.dealextreme.com/p/torch-light-c78-flood-to-throw-zooming-cree-q3-wc-130-lumen-led-flashlight-1-aa-29095?r=29307820) and light up the roads on your daily (nightly?) bike trips!