Design Pattern Library - Stencil Kit

http://developer.yahoo.com/ypatterns/wireframes/

Download a Stencil Kit
Especially for people who have not designed for specific types of interfaces before such as cell phones.

Yahoo! Design Stencil Kit version 1.0 is available for OmniGraffle, Visio (XML), Adobe Illustrator (PDF and SVG), and Adobe Photoshop (PNG), and covers the following topics:

Ad Units
Calendars
Carousels
Charts and Tables
UI Controls
Form Elements
Grids
Menus and Buttons
Mobile - General
Mobile - iPhone
Navigation and Pagination
OS Elements
Placeholder Text
Screen Resolutions
Tabs
Windows and Containers