LaTeXDraw is another GPL'd graphical PSTricks editor for LateX. It is developed in java, so it's independent of the OS, and it's available in English, in Spanish and in French.
Installation. Download and unzip. There is a readme.txt file with instructions, but you need only run 'java -jar installer.jar'.
Configuration. You need to configure some things, but the program lets you know if you try to do something that needs configuration.
Use. Draw. Cut and paste the PSTricks code into your LaTeX document.
Comparison with JPicEdt. Both have their strengths. It seems JPicEdt implements more drawing functions, but that is something that can easily change with some development. I like that one can see the PSTricks code generated by LaTeXDraw as one draws. I also prefer the look of the LaTeXDraw interface.