Hello p (what's your first name please, p sounds very mathematical to me),
By "browse" do you mean use a web browser such as netscape or internet explorer?
No, excuse me, My English is very basic. I mean, read it thorougly, cut the parts of code you thing you understand and use it in your own application to experiment with.
Sketch and Composite Lab are code examples from Apple. You find them and a lot more in the Developer folder, Examples, AppKit. The Developer folder is at the first level of your hard disk.
As for the new PB, try it. You can customize the editors, use gcc 3. And what's unvaluable you have the up-to-date documentation. Personnally, I was at the border of nervous breakdown with the ever mentioned "description forthcoming" each time I needed more details on a method, a class or even a topic.