I am installing gmate on Ubuntu 11.04 (Gnome 3):
sudo apt-get install gedit-gmate
But gedit is untouched (there should appear new themes and plugins).
Those plugins don't work with GNOME 3. In fact, most of the old Gedit plugins don't work with the latest Gedit 3.
The migration of gmate is in progress.
You can try it here: