You should also (in addition to books already suggested) check out Mastering Regular Expressions. Regex's are usually perl's most valuable feature to me, and most of the initial perl coding i did was for basic text processing. This book isn't totally perl-centric, but it makes the subject easier to understand.
in reply to On the matter of Books
Disclaimer: This post may contain inaccurate information, be habit forming, cause atomic warfare between peaceful countries, speed up male pattern baldness, interfere with your cable reception, exile you from certain third world countries, ruin your marriage, and generally spoil your day. No batteries included, no strings attached, your mileage may vary.