Inkscape is is an open-source vector graphics editor similar to Adobe Illustrator, Corel Draw, Freehand, or Xara X. What sets Inkscape apart is its use of Scalable Vector Graphics (SVG), an open XML-based W3C standard, as the native format.
Inkscape supports many advanced SVG features like markers, clones, alpha blending, transforms, gradients, and grouping. It is very easy to edit nodes, perform complex path operations, trace bitmaps and much more.
Current latest stable version available for download is 0.47, which can be downloaded from here.
Requirements : Linux, Windows 2000/2003/XP
License : Gnu General Public License Version 2