Google's Go language (http://golang.org) now considered stable (current version 1.0.2).
- gcc frontend and library for go announced
- one of the language included in http://shootout.alioth.debian.org
Official (and unofficial) editor support:
Vim , Gedit, Kwrite, Kate (Eclipse, Notepad++, Scite), etc.
It might be worthwhile to consider supporting Go in Geany.