Perl Documentation - perldoc.perl.org:Core documentation for the current version of Perl, in HTML and PDF formats. Features include highlighting and linking of code examples, labels, and a customisable display.
A Fresh Look at Efficient Perl Sorting: The Award winning paper presented by Larry Rosler and Uri Guttman at the 1999 Perl Conference.
AnnoCPAN: An "annotated CPAN": a site with all the documentation available on CPAN, along with user-supplied annotations on the margin.
Embedding Perl in HTML with Mason: Book by Dave Rolsky and Ken Williams. Full text freely available.
Extreme Perl: An evolving book about Extreme Programming with Perl. Freely available in HTML and PDF.
HTMLified Perl 5 Reference Guide: by Rex Swain.
Introduction to Perl 5: Highlights new features of Perl 5: a new data type, the reference, and object oriented programming. Designed for those with Perl 4 experience.
Learning Perl the Hard Way: Book aimed at those who can already program in another language; emphasizes programming style. Distributed under the GNU FDL. [PDF/Postscript]
OOPWeb.com - Perl Directory: Perl 5 Documentation by Tom Christiansen and Nathan Torkington. And Perl 4 man page by Robert Stockton.
Perl 4 Manual: Hypertexted searchable index to man.
Perl 5 by Example: Complete text of David Medinets' book, in HTML format.
Perl Crawler Search Engine: The Perl Crawler Search Engine is huge searchable index of all sites devoted to Perl and CGI programming, backed up with a state-of-the-art web indexing spider.
Perl Documentation (FTP): Contains a collection of documents about Perl.
Perl FAQ Index: A list of frequently asked Perl questions with expert answers.
Perl Globe: Get quick Perl reference and begginer tutorials. Function lookup and documentation search.
Perl Medic: Book by Peter Scott about maintaining legacy code. Contents, excerpts, errata, and source code.
Perlfect Solutions - Articles and Tutorials: Articles and tutorials on perl programming techniques. Subjects range from CGI to database access and network programming.