looking to help with green building in exchange for the experience

hey all
I'm really interested in learning about green building techniques, and i know that the best way to do this is first hand experience... i dont really have the money to take a full time course on it, so i'm looking for a commune where some help would be needed for green building projects.
I've already been to an ecovillage on vancouver island, two summers ago, helped them to build a cob and straw bale building, to be a library/ community space...
basically i'm offering free work so i can learn, and hopefully a small place to stay (i have a tent) hopefully i'll be working on a farm in this summer, so i'll have some knowledge of that too....
I'm living in the UK (London), but have friends/family i could use as a 'base' in france or canada (vancouver, calgary, ontario) too, so any of those places would be pretty easy for me to get to.
let me know if you need free help establishing/ expanding your commune space

-robin