I've been wanting do to a post on using the Debugger in Xcode, since that's a topic that had to be cut from the book. Knowing how to debug gets to be rather important as you start writing your own programs, especially as those programs get to be bigger and more complex. Unfortunately, I'm heads down right now trying to get caught up on a couple of different things, and just haven't had the time to do full blog post on the topic.
I did, however, take a break last night to record a short screencast on Debugging in Xcode. There's very little editing in this, so it's not as polished as some screencasts, but if you're new to Xcode or to programming in general, I think you'll benefit from watching it. It shows the basics of using the debugger, including breakpoints, conditional breakpoints, and using breakpoint actions. Click the image to play the movie.