I second the Modern Perl book, which is available both on paper and online

I third the Modern Perl book! :) I really love this little book, authored by an expert Perl programmer and a superb writer (chromatic) ... hmmm, this is probably a rare combination. :) This book gets to the point clearly and succinctly, not wasting time with beginner stuff because it assumes you're already a decent programmer, but new to Perl.

So if the OP is already an accomplished programmer, it's ideal. OTOH, if the OP is new to programming in general, a gentler book, such as Learning Perl, may be a better fit.

BTW in addition to my list of Perl book references (kindly mentioned by haukex) I keep a list of Learning Perl Links.