Inkscape is an open source vector graphics editor with similar features to Illustrator, Freehand, CorelDraw or Xara X, but this is free.
It uses W3C standard, Scalable Vector Graphics (SVG). The program includes a good bunch of features and tools and it can deal with formats like PNG, JPG, BMP or TIFF, it supports layer systems, clones, markers,…
This application can edit XML too, and it includes all main tool included n other really expensive vector graphics editors. Inkscape supports many advanced SVG features (markers, clones, alpha blending, etc.) and great care is taken in designing a streamlined interface. It works really well when editing nodes, performing complex path operations, tracing bitmaps and much more.
The main goal of Inkscape is to be a really powerful and not very difficult to use drawing tool, compatible with XML, SVG and CSS and we can say it achieves it.