best way is to restrict page edits (on every page) only to registered members and make registration harder for spam scripts, e.g. insert some verification picture, like yahoo has
here
This way we keep wiki free to edit for everyone seriously interested in contribution.
Another solution is to lock main page, create subpages like General bot coding, C++ stuff, ... and move links to articles to these editable subpages. This way we protect main page and allow to create new articles (in subpages). Navigation could be a bit less complicated, but sooner or later we would have so many articles ...
Also try to consider this :
http://www.uesp.net/wiki/ Look at their menu on left
