Omnigraffle is this wonderful diagramming and charting package from the Omni Group. PC users, think ‘Visio’ and you have the general idea, just imagine a much nicer interface. Anyway if you’re an Omnigraffle user, you’ll love Graffletopia, a regularly updated site where developers publicize the stencil templates they develop. Check it out if you’re looking to flesh out your Omnigraffle stencils.