Jamesus said it correctly. Devicelock is really a great app. I like slide2unlock's gui better but uninstalled it because it uses so much memory and also because it is buggy on my 6800.
Anyhow, devicelock allows me to:
Assign a key to it, I press the key and the phone locks and goes to sleep in one motion. When I wake the phone up with the power key, I have the option of unlocking it the standard way, or using ONE key.
The one key option is something that was added in version 1.2 at this link:
http://forum.xda-developers.com/show...ght=devicelock
So, you press two buttons to unlock. The power button to wake up the device, and the unlock key, which is mapped to the key above the start key.
Thanks to Matt Armstrong for such a great program.
Enjoy.