1. A computer-implemented method, comprising: at a portable electronic device with a touch screen display, displaying on the touch screen display a user interface for a phone application during a phone call; detecting activation of a menu icon or menu button during the phone call, in response to detecting activation of the menu icon or menu button, replacing the user interface for the phone application with a menu of application icons including an icon for the phone application; maintaining the phone call while displaying the menu of application icons on the touch screen display; detecting a finger gesture on an application icon in the menu of application icons other than the phone application icon; in response to detecting the finger gesture on the application icon other than the phone application icon, displaying a user interface for a corresponding application on the touch screen display while continuing to maintain the phone call, wherein the user interface for the corresponding application includes a switch application icon that is not displayed in the user interface for the corresponding application when there is no ongoing phone call; detecting a finger gesture on the switch application icon; and in response to detecting the finger gesture on the switch application icon, replacing display of the user interface for the corresponding application with a respective user interface for the phone application while continuing to maintain the phone call.