Yesterday I presented "Principles of PHP Package Design" at the monthly meetup of the AmsterdamPHP usergroup. This was quite an experimental presentation. I had prepared it on the same day actually, though I had been gathering the contents of it for several weeks.
Package design is a subject I'm very much interested in and you can be sure to hear more from me about it. Actually, I started writing a book about it! If you're interested too, sign up on leanpub.com/principles-of-php-package-design.
By the way, these are the slides I used yesterday: