Is it possible to create Thiessen polygons around nodes in QGIS?

Is it possible to create Thiessen polygons around nodes in QGIS? e.g. http://en.wikipedia.org/wiki/Voronoi_diagram

Answer

Yes, you'll find "Voronoi Polygons" in Vector - Geometry tools. Additionally, you can access the QGIS and GRASS Voronoi implementation in the Processing Toolbox