Since 1993, several ftp sites have sprung up for Perl and Perl related items. The site with the biggest repository of Perl scripts right now seems to be ftp.cis.ufl.edu [22.214.171.124] in /pub/perl. The scripts directory has an INDEX with over 400 lines in it, each describing what the script does. The src directory has sources and/or binaries for a number of different perl ports, including MS-Dos, Macintosh and Windows/NT. This is maintained by the Computing Staff at UF*.
Note: European users please use the site src.doc.ic.ac.uk [126.96.36.199] in /pub/computing/programming/languages/perl/ The link speed would be a lot better for all. Contact L.McLoughlin@doc.ic.ac.uk for more information. It is updated daily.
There are also a number of other sites. I'll add more of them as I get information on them. [site maintainers: if you want to add a blurb here, especially if you have something unique, please let me know. -spp]
The Comprehensive Perl Archive Network (CPAN) is in heavy development. Once the main site and its mirrors are fully operational, this answer will change to reflect its existence.
Other resources at this site: