With regards to the number of Perl Monks out there, you might find Monk Stats very interesting.
in reply to Perl How Many
With regards to "Perl user", that very much depends on the definition. I've been led to understand that even Windows has a Perl executor somwhere under the hood to do some installation stuff. That would make it a lot of Perl users out there.
On the other end of the spectrum would of course be people who make a living programming in Perl on a daily basis. Personally, I would think there are at least 10's of thousands out there. But that's just a guess, based on the amount of books published about Perl and estimating what the break even point of a published book is.