[ Christiansen+ 98] Christiansen, Tom, and Nathan Torkington. Perl Cookbook. Recipes to do all types of tasks in Perl.
[Conway 99] Conway, Damien. Object-Oriented Perl. A complete introduction to the object-oriented features of Perl. A must-read for those wanting to learn how to use Perl for object-oriented programming.
[ Friedl 02] Friedl, Jeffrey E. F. Mastering Regular Expressions. An excellent book covering a complex topica must have for those of us creating complex regexes.
[Hall+ 98] Hall, Joseph N., and Randal Schwartz. Effective Perl Programming: Writing Better Programs with Perl. A very good book discussing many advanced features of Perl, including references and modules.
[Schilli 98] Schilli, Michael. Perl Power: A JumpStart Guide to Programming with Perl 5. A good introduction to the language.
[Schwartz+ 01] Schwartz, Randal L., and Tom Phoenix. Learning Perl, Third Edition. An excellent introduction to Perl.
[Stein 01] Stein, Lincoln D. Network Programming with Perl. If you want to use Perl to write network programs, get this book. An excellent treatment of networking with Perl.
[Wall+ 00] Wall, Larry, Tom Christiansen, and Jon Orwant. Programming Perl, Third Edition. The bible, Larry Wall version. Read it, study it, grok it.
Perl in 20 pages: www.best.com/~quong/perlin20/
Tom's object-oriented tutorial for Perl: http://language.perl.com/all_about/perltootl
University of Missouri Tutorial: www.cclabs.missouri.edu/things/instruction/perl/perlcoursel