As per the Apple iPhone Human Interface Guidelines I have created a Default.png image which is displayed while waiting for the application to load.
I created the image u
The easiest way I found is to use the special "Copy Screen" menu option in Simulator.
While the Simulator is running, hold the control key. The Edit menu will change from "Copy" to "Copy Screen". You now do a Command-V in Preview or Photoshop since the screen was saved to your clipboard buffer. Then save out the file as png.