Change network "name" of MacBook Pro?

I logged into my router today to see what was connected to it. I found all my computers and devices, but my MacBook Pro was listed as a blank space for the hostname
For example, my appletv has "AppleTV" listed as the hostname
i cant find anywhere to change it on my macbook

thank
brett

If you are on Tiger, Leopard or SL, go to System Preferences and select "Sharing".
Give any desired name under "Computer Name" (You should be an admin user to change this).
That's all

yeah i tryed that and it did not work