Essential Perl 5 for Web Professionals by Micah Brown, Chris Bellew, and Dan Livingston. Published by Prentice Hall.
This small book aims to get you up to speed on using Perl in the context of a web site. It does not assume a prior knowledge of Perl. With this book you could get some simple CGI interactivity on your site.
If you have no familiarity with Perl this would be a good start. I would not use the scripts on a live web site. They need to have security measures put in to avoid malicious users. Security does not appear in the index. That said this is an accessible book and the examples use situations you will recognize.
I think a better general introduction to Perl is Learning Perl by Randal Schwartz.