This plugin uses pygments to highlight code on the server, with a simple shortcode. For example, [pyg]print "Hi"[/pyg]).
This plugin depends on the command "pygmentize" being in the web server's path. With Ubuntu or Debian, this can be achieved by typing
sudo apt-get install python-pygments
After that, install this plugin like any other. Go to Admin > Plugins > Add New > Upload. If that's too easy for you, try this: