If anyone's interested I just posted directions for building a woodgas stove on my blog:
http://intotheborderlands.blogspot.com/2008/01/homemade-wood-gasifier-stove-revisited.html

Woodgas stoves are twig-burners which preheat the air used in combustion. This hot air vaporizes assorted flammable molecules out of the wood and these molecules are what burns in the first half of the run. The twigs are converted to charcoal as these molecules are burned off (think making charcloth). After all these volatile compounds have burned off the charcoal begins burning and burns all the way down to a small amount of ash.

Not bad for three tin cans and a peice of steel mesh.

Sidenote: there are a lot of large pictures in the post so those of you on a dial-up connection might have a slow time with it. Sorry about that.

Sidenote #2: As with a alcohol stove, do NOT replace the recommended fuel (twigs) with Coleman fuel/kerosene/gasoline/cat/etc.

-Blast