Due to high demand, this very nice vector-based drawing program has been SourceForge.net's Project of the Month a month ago.
What is Inkscape?
Inkscape is a vector-based drawing program, like CorelDraw® or Adobe Illustrator® from the proprietary software world, and Sketch or Karbon14 from the free software world. It is free software, distributed under the terms of the Gnu General Public License