I just finished setting up gedit to emulate textpad for ruby development. after using the links below you should have the closest thing to textmate on unix
first things first
http://www.thaumatocracy.com/news/textpad-for-linux/
next
http://rubymm.blogspot.com/2007/08/make-gedit-behave-roughly-like-textmate.html
extra
grigio.org has a good over view of plugins :
http://grigio.org/textmate_gedit_few_steps
also grab his gedit color scheme (near end of page)
Tags: gedit, how, linux, news, plugin, plugins, ruby, setup, textmate