IDea Go plugin. No refactoring available yet: http://plugins.intellij.net/plugin?pluginId=5047

Vim plugin. No refactoring available yet: http://go-lang.cat-v.org/text-editors/vim/

Eclipse plugin. No refactoring available yet: http://code.google.com/p/goclipse/

Others (afaik- no refactoring available yet): http://go-lang.cat-v.org/text-editors/