Hi Robert,
On Xcode 3.2.5, I select File > New Project and then a window pops-up with the following options:
Choose Other > ArduinoOnXcode.
I don't know how it runs on Xcode 4 but I guess it's similar.
I still don't manage to get my own libraries compiled, as Example-4 attached in a previous post. There's no problem with standard Arduino libraries.
Nice to hear from your progress 