Dan Saffer of Kicker Studio provides free touch screen gesture stencils for OmniGraffle, Visio, Illustrator, and Fireworks. The icons are designed by Rachel Glaves for Saffer's book, Designing Gestural Interfaces, and depict hands performing common touchscreen gestures like tap, slide, point, drag, pinch, and spread.
http://www.kickerstudio.com/blog/2008/12/touchscreen-stencils/