Yahoo! Stencil Kit is a set of graphics to help you create mockup designs real quickly – you can use these stencils for designing web pages for the desktop or mobile phones.
And even if you are no web designer, you may use Yahoo! Stencils to create illustrations. For example, you may place screenshots inside the BlackBerry mockup that comes in kit or try different placements of the keyboard on the iPhone screen.
The graphics are available as PDF, Visio, SVG (Illustrator) and PNG (for Photoshop).