can anyone hint me to a good and free webboard/forum system ?! I plan to open one but I dont want to pay money for it. 
Yeah, I can really recomend phpBB. Easy as pie to install, customize and maintain.
I would recommend SMF. I’ve yet to set up a forum of my own (I plan to) but from the user’s point of view it’s the best simply because it has a working tracking of new posts. Post are marked old only after you have read them, it’s not based on time or sessions.
Weird license (not familiar with it), how does that prevent usage? “Real templates”?
Well, templates for separating design and code. With templates you can skin up the software for your needs without knowing how the code works 
Not afraid of code.
I think I go with phpBB, I found a guy in my city who has set up a few boards with this system, so I have some help.