Pencil Project

Pencil Project is a free, open-source tool that you can use to design web prototypes. It's a big help for designers and developers, since it allows you to quickly and easily put together document proposals for clients. So, you can outline a whole website in the same file, exportable to PNG, HTML, or PDF format. Pencil Project gives you the option to design your own templates and create prototypes, as well as standard drawing operations: alignment, z-order, scale, rotation, dimensions, etc. Finally, you can export your work into many different formats, including images, PDF, OpenOffice, and more.