I have just GOT to second this - that book by Damian is my Bible. I use it every single day. I have been known to sleep with it - dare I say I "know" it in the "Biblical" sense? (I couldn't resist.)

My first foray into Perl's OO realm was actually just with packages. I wrote a wrapper for another module. Though not OO, it made me familiar with the world of packages - it was of immense value once I dove more deeply into OO.

For true OO, I took apart someone's CPAN module and started re-writing it - another good experience. After that, I was ready to make my own.

Good luck!