It can depoend of the distribution you installed.
Assuming redhat or mandrake, you find network stuff under the following dirs.
/etc/sysconfig
/etc/sysconfig/network-scripts
hostname is set in /etc/sysconfig/network
ip for each nic is set in /etc/sysconfig/network-scripts/ifcfg-ethx where x is 0-n.
just poke around and look at the man pages for files in these dirs.