1. perldoc perlstyle - I don't follow all the advice, but it is good.

2. Perl Best Practices - It is a good coding set of standards. I don't agree with all of it, and you won't either, but it is good food for thought. (It is very hard to come up with coding standards that are decent for all situations. Damian has succeeded at that. But for specific situations, it is easy to improve on it. Unfortunately it is the nature of the beast that one chance undermines the next rule and you wind up needing to change more than you think. Read it, think about it, and you'll see what I mean.)

3. Code Complete - A classic. If I had my druthers, every programmer would be made to read it. And quizzed until they re-read it until they understood it.

Cheers,
Ben