1. A computer-implemented method, comprising: at a portable electronic device with a touch screen display, displaying a list of voicemail messages; detecting a scrolling gesture by a user on the touch screen display, wherein the scrolling gesture comprises a substantially vertical movement of a finger of the user on the touch screen display; responding to the scrolling gesture by scrolling the list of voicemail messages; detecting selection by the user of a respective voicemail message in the list, responding to the user selection of the respective voicemail message by initiating playback of the user-selected voicemail message, and displaying a progress bar for the user-selected voicemail message; detecting selection by the user of a backup icon; responding to the user selection of the backup icon by backing up the playback of the user-selected voicemail message by a predefined amount; detecting selection by the user of a speed up icon; responding to the user selection of the speed up icon by increasing the playback speed of the user-selected voicemail message; detecting movement of a finger of the user from a first position on the progress bar to a second position on the progress bar; and responding to the detection of the finger movement by restarting playback of the user-selected voicemail message at a position within the user-selected voicemail message corresponding substantially to the second position on the progress bar.