https://help.ubuntu.com/community is yet another wiki, this time for the entire community to contribute their documentation to. So if you want to let the world know how you got something specific setup, head on over there and setup a wiki page.
https://wiki.ubuntu.com is more or less the staging area for Ubuntu, Kubuntu, Edubuntu, and Xubuntu development. You will notice a lot of things specific to development, artwork, specifications and such.
No matter if you work on the Community Wiki or the Development/Staging Wiki, there is a Styling Guide to follow. If Wiki hacking is your thing, you might be interested in the Ubuntu Wiki Team. They are a part of the Ubuntu Documentation Project and communicate on the ubuntu-docs mailing list and on IRC in #ubuntu-doc.
NOW! Calling all documentors! We need your help with content in the Edubuntu Handbook as well as the new Kubuntu System Documentation. The Doc Team utilizes DocBook XML however if plain text works for you, it works for me. You can always send the text files directly to me and after a quick run through I will manually put them to DocBook files. We work from a Subversion Repository so there are only a select group of individuals who can commit, however anyone can check out, edit, and submit patches to ubuntu-docs(at)lists.ubuntu.com.
If anyone is interested in helping out, try and stop by #ubuntu-doc on IRC (chat.freenode.net | port 8001). Thanks everyone!