Phil Boswell wrote:
I don't consider myself up-to-speed enough in PHP to contribute actual code, but I would like to help in documenting what's there.
If you're talking about commenting the source code, you can submit patches for that here.
If you're talking about helping with writing the User Manual, that's at http://meta.wikipedia.org/wiki/MediaWiki_User%27s_Guide.
Greetings, Timwi