http://www.micahcarrick.com/09-29-2007/gedit-html-editor.html
A nice article on how to mod the hell out of gedit to make into a pretty powerful ide. Some really good plugin recommendations and some custom code. Nice job. :-)
http://live.gnome.org/Gedit/Plugins
A list of plugins available for Gedit. Useful resource.
http://grigio.org/pimp_my_gedit_was_textmate_linux
A post on pimping Gedit to make is something like Textmate (proprietary mac editor). Includes tips on some useful plugins and how to tweak settings. Worth checking out.