I just want to share this with you guys as it looks very useful for mocking up iPad UIs. It’s called the iPad GUI PSD, and can be downloaded and used in PhotoShop. Everything can be scaled easily as the elements are vector based. Thanks go to Teehan+Lax for this useful resource.
Lisa Marie Ortega 
Caution: Read this before attempting to design with this.
Aside from the points made by Sebastiaan above, I’m fairly sure that all the basis of the work is from the simulator in the new 3.2 beta SDK. The problem there, is that it falls under Apple’s rather draconian non-disclosure agreement (they’d dropped it for previous releases, but it’s back in force for this new beta.)
It’ll be interesting to see if Apple’s legal eagles swoop down on this…
How do I edit this template? When I open it up in Photoshop it’s just a flat image.
Am I doing something wrong?
@Stockit When I open it up it is a layered editable image so i’m not sure why you’re only getting a flat image. Perhaps email the creators of it if you’re still having problems.