Here are a bunch of handy arguments taken from this page:
Redhat Documentation
So, typically I interrupt a Redhat boot and choose the following:
(appended to the normal boot line)
ksdevice=eth0 ip=10.2.3.4 netmask=255.255.254.0 gateway=10.2.3.1 dns=10.10.10.2,10.10.10.4 ks=http://url/to/my/kickstart.cfg
