Teehan + Lax have created a great Photoshop document that makes mocking up an iPhone UI a lot easier. The psd includes a comprehensive library of assets, that is fully editable.  I have been very pasionate about the iPhone since the first day it came out. And fortunately, I just came across this post right when I am about to begin working on an iPhone related project.

Download from: TeehanLax.com

Via: iso50 blog