Some functions can be accessed using the Fn key. Screen brightness can be controlled using Fn+Home and Fn+End. Internal/External/Both displays can be cycled trough using Fn+F7. Those combinations work without any extra effort (though the tpb package below adds on-screen-display support for the brightness level). Fn+F4, lid close and the power button are reported as acpi events (which can be acted upon using acpid as detailed in the suspend section).

Additionally there are two keys located by the keypad, tentatively called forward and backward. These keys generate regular keyboard scancodes, so they can be assigned to actions using the regular keyboard shortcuts application under GNOME (and I assume there is something similar for KDE).

Finally, the keyboard has four non-standard buttons: "Access IBM" (which is the same as the "Thinkpad" button on some other models), volume up, volume down and mute. The buttons can be handled by including nvram support in the kernel and installing the tpb (ThinkPad Buttons) package (can also be found here if your distribution doesn't carry it). Edit /etc/tpdrc to your liking and everything should be good to go. Audio and brightness should now be tunable using special keys and the changes should also be displayed on screen in X using the libosd package.