I recently worked on a couple of user experience specifications for mobile applications with Adobe InDesign and Illustrator and, while I found many resources for Omnigraffle, I couldn’t find anything for Illustrator. Most of the stuff I found was for Omnigraffle. I never particulary liked Omnigraffle , so I sticked to Illustrator and Indesign. There are some visual design templates available on the web, but I find using visual design elements in wireframes totally misleading, they make the clients focus on the wrong things: wireframes should only be used to communicate functional elements of the page, and give some indication on the real estate taken by these elements. I created a .ai and .pdf file with most of the assets I have used with these two apps. While it is not a complete set, it should be useful to avoid recreating the same stuff if you find yourself in the same situation.
I am going to do something similar in the next weeks for Android applications, where there is even less abundance of design resources… Iphone wireframe elements [.ZIP file] 
iPhone wireframes template by G iorgio Venturi is licensed under a Creative Commons Attribution 3.0 Unported License.
[...] it.iPad Vector GUI Elements (.ai)iPhone Sketch-Like Elements (.ai)iPhone UI Vector Elements (.ai)Illustrator Template for iPhone Design (.ai) Creative Commons Attribution 3.0 Unported License”>iPhone 4 Vector Template (.ai & .eps) [...]
[...] Illustrator Template for iPhone Design (.ai) [...]
[...] Illustrator Template for iPhone Design (.ai) [...]
[...] Illustrator Template for iPhone Design (.ai) [...]
Thank you very much for your effort, i’ve made an iPhone app and I had to build my own like yours too, this is great, I also found useful files on Yahoo! UIs Library. thanks again.
[...] Illustrator Template for iPhone Design (.ai) [...]
[...] Illustrator Template for iPhone Design (.ai) ? [...]
@Mohammed You welcome!
Did you ever end up making a similar template for Android?
[...] http://www.usercentred.net/2010/06/28/illustrator-template-for-iphone-design/ [...]
thanks..this is handy
[...] Illustrator template for iPhone design [...]
Thank you so much for this template. That is really helpful!
Great, thanks for posting this, it may very well come in handy.