Komodo anyone?
There is a promo code which gives you the personal edition of Komodo for free ;) As a late Christmas present from ActiveState.
Well worth the effort for a IDE and is built upon Mozilla's XUL framework.
Award-winning IDE for dynamic languages, providing a powerful workspace for editing, debugging and testing your programs. Komodo offers advanced support for Perl, PHP, Python, Ruby, and Tcl. Komodo runs on Linux, Mac OS X, Solaris, and Windows.
UPDATE:
The offer ends on December 31st 2005.