He registered as an Apple developer at developer.apple.com. You do need a Mac to develop an app because Xcode, the program used to write apps in Objective-C, only runs on the Mac OS.
If you are interested in designing an application and distributing it through the App Store you can follow the iPad and iPhone app development course from Paul Hegarty at Stanford on iTunes U. Assignments and PowerPoint slides are included. I watched the first lecture and learned a little about MVC (model view controller) design strategy. It assumes a certain comfort level with object-oriented programming, which I do not have, so he pretty much lost me at the introduction to Objective-C.
This image has Paul’s first ever app on the simulator that comes with Xcode.
Stay tuned for more homegrown apps updates!