Sketching & GUI Prototyping, FREE & OPEN!
Pencil will always be free and can run on virtually all platforms that Firefox 3 supports.
The Pencil Project's unique mission is to build a free and opensource tool for making diagrams and GUI prototyping that everyone can use.
Pencil will always be free as it is released under the GPL version 2 and is available for virtually all platforms that Firefox 3 can run. The first version of Pencil is tested against GNU/Linux 2.6 with GTK+, Windows XP and Windows Vista.