We're been working hard to create a simple-to-use alternative to Arduino for people getting started with hardware. All of the code was written using Processing and is open source for everyone to explore.
You can download the latest version of Teagueduino from the project's website and open the "source" folder. You'll notice that the app is quite involved with custom dialogs, realtime graphing/feedback, protocol interpretation, serial communication, and networking with a project server. It took quite a bit of time to get it where it currently is, so I'm hoping others might find it useful when building their own Processing apps.
