There is a south african blog with step by step instructions about building a treehouse.
If anyone is interested, here the link:
http://ropesandpoles.blogspot.com/2005/12/treehouse-step-by-step-main-page.html
If anyone is interested, here the link:
http://ropesandpoles.blogspot.com/2005/12/treehouse-step-by-step-main-page.html