When I press the "Suspend" key combination (Fn+F1) on my Lenovo T61 or X61 ThinkPad, nothing happens. How can I suspend my system?

Updated -

The "Suspend" key combination (Fn+F1) does not work at this time on Lenovo T61 or X61 ThinkPads. It is recommended that users left-click on the Power Manager applet in Gnome and select "Suspend" or "Hibernate" in order to put the laptop into suspend or hibernate modes.

Note that suspend/hibernate/resume do not work with the xen kernel. You must use a non-xen kernel.