Binary package “indicator-session-gtk2” in ubuntu precise

indicator showing session management, status and user switching

 This indicator is designed to be placed on the right side of a panel and
 give the user easy control for changing their instant message status,
 switching to another user, starting a guest session or controlling the
 status of their own session.
 .
 It requires some way to be hosted into a panel. For the GNOME Panel the
 appropriate package is indicator-applet-session.