No as Ralph said the 'simulator' is a stand alone app that you can use to simulate the ipad and iphone/retina. You do have to download the whole xcode to get it (which is a bit of a pain) but then you can just stick the simulator in the dock and then drag or type urls in the address bar to browse as usual. It works on local files also so is ideal for testing.
You can test in portrait and landscape mode and the mouse imitates touch gestures and you can even test two finger scrolling and zoom and pinching with a combination of keys.It is more or less 100% accurate as you would expect as it s also meant for app development. Of course nothing beats the real device as there are always nuances in how a mobile really works and displays.