Inkscape is an vector graphics editor with sophisticated drawing tools with capabilities similar to Illustrator, Freehand, and CorelDraw. It uses the W3C standard scalable vector graphics format (SVG) but can import and export several file formats such as EPS, PDF, PS and PNG.
Inkscape's functionality can be further customised with addons.
Check out Tavmjong Bah's "Inkscape: Guide to a Vector Drawing Program" and FLOSS Manuals : Inkscape
If you have an older version of Inkscape installed, you should remove/uninstall the previous version before updating.