In accordance with some embodiments, a computer-implemented method is performed at a portable electronic device with a touch screen display. The method includes: displaying graphics and an insertion marker at a first location in the graphics on the touch screen display; detecting a finger contact with the touch screen display; and in response to the detected finger contact, expanding the insertion marker from a first size to a second size on the touch screen display and expanding a portion of the graphics on the touch screen display from an original size to an expanded size. The method further includes detecting movement of the finger contact on the touch screen display and moving the expanded insertion marker in accordance with the detected movement of the finger contact from the first location to a second location in the graphics.