Frustrated with Xcode 4.4 and it's lack of Go Language support, I managed to hack a couple of template files that make things a little more bearable.
Clone this repo, and copy the Template directory in the top level to ~/Library/Developer/Xcode
Restart Xcode.
When you create a new project, you should have a new Project Type of Go under OSX and a way to create go source files.
We still have the issue of having to mark the Syntax Coloring by hand, with the stuff that is is in $GOROOT/misc/xcode/4/