Well, you already found the Monastery (i.e. Perlmonks), arguably the best site for learning Perl. ;) The perldoc site is very useful as a reference, as is perl.org itself. CPAN is a treasure trove (and meta::cpan is a great way of accessing it). That's about what I can think of right now; no doubt other, more experienced monks will know more.

Just because I love killing trees (or electrons, as the case may be), here's some suggestions for books as well, both old and new:

• Learning Perl, aka "The Llama" (June 2011)
• Beginning Perl (August 2012)
• Intermediate Perl, aka "The Alpaca" (July 2012)
• Mastering Perl (January 2014)
• Programming Perl, aka "The Camel"; a must-have (February 2012)
• Modern Perl (April 2014; PDF here)
• Advanced Perl Programming (June 2005)
• Perl Best Practices (July 2005)
• Effective Perl Programming, aka "The Shiny Ball" (April 2010)
• Perl Cookbook (August 2003)
• Perl Hacks (May 2006)
• Perls of Wisdom (December 2004)
• Introducing Regular Expressions (July 2012)
• Mastering Regular Expressions (August 2006)
• Mastering Algorithms with Perl (August 1999)
• Higher-Order Perl (March 2005; PDF here)
• Perl Testing (July 2006)

There's also many books dedicated to specific topics such as Perl/Tk, DBI, Perl and XML, CGI programming with Perl, and much much more.