I've installed XCode 3.2 on top of Snow Leopard 10.6.2. When trying to "build and run" an application created from XCode template, the emulator is always opened in iPad mode. When choosing "iPhone" from the emulator menu, it changes its look but next time it is opened as iPad again.
How to cause the emulator to run in iPhone mode ?
It seems that it was answered here http://stackoverflow.com/questions/2413948/setting-xcodes-target-to-iphone-not-ipad
The XCode 3.2.3 comes with SDK 4.0, which is the only choice for building for iPhone OS4, does not provide the right iPhone Simulator! If you pick "Simulator 3.2", it always comes out the iPad Simulator, and your iPhone app does not simulate there properly. If you pick "Simulator 4.0", though the UI looks like a iPhone, but functions are still not responding, e.g. tables cannot roll, maps cannot move, etc.
No other SDK options in XCode 3.2.3.
In the end, I installed the previous XCode 3.2.1 with SDK 3.1.3 into another directory, to Simulate with SDK 3.1.3, and build into the iPhone OS4 with the XCode 3.2.3 from SDK 4.
Not sure whether Apple will change their future versions of SDK 4.0+XCode 3.2.3 to provide a correct, working, iPhone Simulator.