Our server documentation is a complete mess at work. One of
the things I’ve been considering is converting it all to a wiki,
something thats easily searchable and extendable.
To that end, I’ve done a little (read: 10 minutes) research into
installing PHP on a windows server using IIS. This page seems to
have some quite useful info.
At the moment, DocuWiki
is my favoured choice. It’d be very handy to find a wiki with
ability to import from Microsoft Word documents, but I really doubt
such a wiki exists.
Unfortunately, DocuWiki seems to have a few rendering problems under
IE, and being a Windows-based team, most people seem to use IE 🙁

http://tikiwiki.org/tiki-index.php?page=TikiWiki seems to be another
reasonable one. It even has a macro to convert word documents
into wiki format!
(http://tikiwiki.org/tiki-index.php?page=WordToWiki_swythan&bl)