A new-format language "mode" for SubEthaEdit 2.x is available
VIM has been done by Alessio Pace
Guillaume Laforge wrote a syntax file for the TextPad text editor which can be downloaded
here. This file should be installed in the Samples subdirectory of your TextPad installation.
Jeremy Rayner has written a groovy-mode for emacs, details of which can be found on the Emacs Plugin page.
Find more info on the UltraEdit Plugin page.
Syntax files have been created for Crimson Editor by Jim Ruley. Crimson Editor is a versatile freeware source code editor for Windows. Syntax-highlighted Groovy scripts can be run, and output viewed, directly from the editor. See the Crimson Editor site for more information.