ScrollView
reference: http://www.androidaspect.com/2012/02/scrollview-tutorial-android-ui.html
iOS, Android, Unity3D Education blog,
reference: http://www.androidaspect.com/2012/02/scrollview-tutorial-android-ui.html
sample code: Tutorial_UI_ScrollViewActivity
reference: http://code.google.com/p/deezapps-widgets/source/checkout