Inkscape is an Open Source vector graphics editor, with capabilities similar to Illustrator, Freehand, CorelDraw, or Xara X using the W3C standard Scalable Vector Graphics (SVG) file format.  Although it’s not as powerful as the forementioned products Inkscape is vastly capable of producing high-quality vector based drawings with a slick, easy-to-use interface.  Casual users (on most platforms) should respect the fact that Inkscape is Open Source, which makes it Free, Community Supported, and Open to Change Based on User Feedback. AltHack.com is currently using it to make diagrams for our upcoming tutorials including our NES Controller Mod.  So, what are you waiting for?  Check them out! http://www.inkscape.org/