A good place to start is perltoot, and you can use perlobj, perlboot, perltoot, perltooc, and perlbot for reference. (If you are using really old Perl, you may not have all of these, try http://www.perldoc.com/ , but consider upgrading your perl.)
A good book on OO on Perl is the "Object-Oriented Perl" by Damian Conway from Manning Publications, http://www.manning.com/Conway/index.html