Component packaged with Joomla! 1.6 Core.
Select Site → Site Maintenance → Global Check-in from the drop-down menu of the Joomla! Administrator Panel.
Selecting this menu option will cause Joomla! to perform a global check-in of all currently pending or locked items. It then shows the results of the Global Check-in. This is useful, for example, if an Article is locked by a User who opened it for editing and never finished the editing session. In this case, other Users are not able to edit this Article. Performing a Global Check-in releases all such items.
At the top right you will see the toolbar:
(Icons need 1.6 update)