The Mono / MonoTouch Soft Debugger
Honestly, I thought that it was really cool when the Novell guys put a soft debugger into Mono/MonoTouch so that it is possible to debug an application running on the iPhone Simulator or on the actual device. Basically, its a set of code inside of MonoTouch that will talk back to the debugging device. According to the document, it works in the simulator, an iPhone attached to your macintosh, or over wifi if you are ont eh same network. Thanks guys!
Want to know more about developing with the iPhone? Check out my Wrox Blox eBook on developing applications with MonoTouch for the iPhone/iPod touch for .NET/C# developers.