I have a collection of Perl books and the one I think would be best for a classroom setting is Perl How To Program
by Deitel, Deitel, Nieto, and McPhie. You can get just the book or a multimedia cyber classroom version. I took a college course in Java using their multimedia cyber classroom version and thought it was very good. That experience is what prompted me to buy their perl book.
I have the camel and llama books but it seems to me that they are for the more motivated people that just pick the book up to learn on their own. The Deitel book was written for a classroom environment and has self-review exercises and exercises.
There are some errors in the book, but I still use it as a reference for regex and it's the book that I first used to learn CGI.