If you're just starting to think about incorporating user centered design processes into your next web site, you've probably heard about wireframes. They're outline drawings of the different pages, much like blueprints for a house. They're useful for many reasons, including making it easier for you to explore usability and design problems, review them with others, and quickly revise your plans. We've put together lots of wireframing resources for you:
Comments
People interested in wireframes should also consider iRise which lets users create both low fidelity wireframes and high fidelity simultions or fully functioning prototypes.