It's usually attributed to Terry Pratchett. It appears in Jingo.
Terry generally makes up his own wisecracks, and does a very good job of it.
Cheers, Ben
"good ideas and bad code build communities, the other three combinations do not" - [link|http://archives.real-time.com/pipermail/cocoon-devel/2000-October/003023.html|Stefano Mazzocchi]