I have now completed a web based syntax highlighter that can prettify any code that is already available on the net (like via WebCVS/SVN, or just plain uploaded files). It has support for Java, Python, C++ and Ruby among others. To use it, simply enter a URL to some code you want to be highlighted and decide if you want line numbers or not. You can also chose to only retrieve a link that you can use on your own homepage/blog/forum/whatever.
You can find the tool in the sidebar, or simply by clicking here.