we've been saved by TWiki
we installed TWiki (www.twiki.org) a couple of years ago as a way to organize our collective information for implementation and support.
it has proven to be the most critical decision we made on the project - anybody can author articles, completely searchable, linkable within twiki as well as to external information, etc.
we started small and have just continued adding more information as time goes on. we've grown several FAQs, as well as best practices, installation and operating procedures, vendor documentation, etc.
it's free to try, and you'll quickly see the benefits of having a "collective" mind!