Inkscape is an Open Source vector graphics editor, with capabilities similar to Adobe Illustrator, CorelDraw, or Xara X, using the W3C standard Scalable Vector Graphics (SVG) file format. Its compatible to Linux, Windows & Mac OS X.
It features transparency, gradients, node editing, pattern fills, PNG export, and more. Aiming for capabilities similar to Illustrator, CorelDraw, Visio, etc. Inkscape supports many advanced SVG features including markers, clones, alpha blending, etc.
It has a great, streamlined designer interface. It is very easy to edit nodes, perform complex path operations, trace bitmaps and much more. Download Inkscape