Inkscape is an free vector graphics editor, with capabilities similar to Illustrator, Freehand, CorelDraw, or Xara X, which uses the W3C standard Scalable Vector Graphics (SVG) file format. Supported SVG features include shapes, paths, text, markers, clones, alpha blending, transforms, gradients, patterns, and grouping.

inkscape You can read more about it here.

If you are planning to download it, make sure you get the Windows ".exe installer" version.