Important publications
Programming Perl, 3rd ed.
The Camel, the real Bible of Perl.
http://www.amazon.com/dp/0596000278
Learning Perl, 4th ed.
The Llama, the standard Perl tutorial
http://www.amazon.com/dp/0596101058
Perl Cookbook, 2nd ed.
Now in its 2nd edition, a problem-oriented book of how to do just about everything.
http://www.amazon.com/dp/0596003137/
Object Oriented Perl
By Damian Conway, the best explantion of how to do standard Perl 5 object-oriented programming.
http://www.amazon.com/dp/1884777791/
Perl Best Practices
Damian's follow-up to Object Oriented Perl shows how to write good, maintainable Perl code.
http://www.amazon.com/dp/0596001738/
The Perl Review
Published here in Chicago, it's the only magazine devoted to Perl.