I think you might be able to change it in the GUI with redhat-config-network
. Otherwise edit your /etc/hosts file and create an /etc/hostname file with just the hostname in it.
# Celeron 850 tinwhistle /etc/hosts file
127.0.0.1 tinwhistle localhost.localdomain localhost
My /etc/hostname file:
A logical name would be a name that you like to use for your computer.
Personally, I never liked the name My Computer....