Changing "localhost.localdomain"

["Manuel Camacho" <mcamacho conexion co cr>]

I have a desktop computer at home running RH 7.2. I connect to the net 
using rp3 by means of a modem connection (no LAN, WAN, not even a network 
card on this box). In my consoles and prompts I 
get "localhost.localdomain", which I would like to change to other text, 
i.e., "naming" my computer. 

How can I do this?

Displaying "computer's name" rather than "localhost.localdomain" has 
nothing but an esthetic meaning to me.

Thanks a lot,

-Manuel.