[Q] Using Go Dialer to Call

[livingincm]

I was messing around with my galaxy S and the phone's dialer & contact disappeared from the home screen & went to look around the market and found go dialer & contact and manage to make phone calls out of it via your cellular plan. Has anyone (with 3g + voice plan) tried downloading this app & tried phone calls? Or will it just come back with a "invalid device" error or sth?