If your building an app your pretty much guaranteed to have to use the iPhone Simulator. However in all the excitement it seems that Apple have forgotten to update the simulator graphics to reflect the fantastic new design.
So i had a little peak in to the iPhone Simulator.app bundle... and then i opened photoshop ... and i ended up with this
Initially the main take away, is that you can upgrade the appearance of your simulator to reflect the device of your choice, however realistically you could replace the image with anything you like.
Incase you want to do this for yourself, follow these steps
1. go to where you have installed xcode, usually /Developer
2. From there goto /Platforms/iPhoneSimulator.platform/Developer/Applications/
3. Control/Right click on the iPhone Simulator.app and select show package contents
4. Open and edit the frame.png image to your hearts content.
For the image above, i used the iOS4 UI mockup PSD from Geoff Teehan