Aside from the resources mentioned above, you may want to take a look at * Damian Conway's Object Oriented Perl from Manning. I've been reading it the last few weeks and it's going a long way in clarifying terms that kept popping up more and more for me while learning Perl. (ie: polymorphism and inheritance)

An additional approach is to look at another language that puts as much if not a greater emphasis on object oriented programming. Learn the general OO principles and reinforce that knowledge by comparing how other languages implement them to Perl. * This is part of a suggestion offered to me by a few friendly monks (right now I'm applying the advice in comparing functional languages to Perl).

Good luck!

* Others may be turned off by the 1999 publishing date but I feel pretty good about what I've learned so far.

* The thinking is that in learning various languages that are different stylistically you gain greater overall knowledge of programming practices and concepts.