The "Squeak Swiki" is a large and active Wiki that documents SqueakSmalltalk. You will see many references to its old home at http://minnow.cc.gatech.edu/squeak , but most page addresses can be translated to its later address at http://wiki.squeak.org/squeak where it moved in the mid 2000s.
Of the Squeak-based Wikis, the Comanche swiki was for a long time the most popular codebase: http://wiki.squeak.org/swiki/
I have used an old version of SqueakWiki for years as a way of storing personal content. My main problem with this is how to convert the information into other formats which did not exist when I started. -- JohnFletcher