Ask HN: How best to teach object oriented programming?

Hey there HN, so I've just gotten a job tutoring a highschool freshman how to program. He has a little programming experience, but not much; I'm not sure with what language. I've been programming in python and C for the last couple of years, and only recently started messing around with Java. I know most of the principles of object oriented design, but I've never tutored anyone before or had to explain object oriented programming to anyone. Eventually, the kid wants to learn how to program iPhone apps, but he understands that I've never done that before and we both think it would be best if he learned the fundamentals of programming first.

Are there any particularly good books I should read / have the kid read? He's open to a bunch of different languages - I figured I'd cement the basics of programming in general with python and then introduce him to object oriented programming in particular with Java (using BlueJ as the IDE because it automatically shows class structure). Do you think there would be a better way to go about it? Thanks, peter_l_downs