in reply to
Free Stuff: chromatic's introductory and freely downloadable Modern Perl.
Not-Free Stuff: After digesting Modern Perl, the Camel book, and the various on-line introductions and tutorials here and at perldoc.perl.org, Perl Best Practices (PBP) is a bracing read. I certainly don't endorse all the "practices", but I think the discussions of each practice and its rationale are well worth one's time and attention.
And BTW: The language is named Perl, and the interpreter executable is named perl.