jEdit is a programmer's text editor written in Java. It uses the Swing toolkit for the GUI and can be configured as a rather powerful IDE through the use of its plugin architecture.
This is the Mel syntax highlighting mode file updated for Maya2008. It includes new Mel commands, API classes and nodes. It also includes an updated python syntax highlighting mode file that includes the Mel commands, API classes and nodes when scripting Maya from python. The included 'catalog' file demonstrates how to specify the various modes and make sure jEdit can recognize them.
Download jedit from:http://www.jedit.org
Tutorial on how to set it up for Maya:/maya/tutorials/using_tools_scripts/Configuring-jEdit-with-Maya-319.html