Dana,

Saw your post on KCLUG, and thought I'd offer my help, if you have not already figured it out.  The 
response I saw related to plugging the linux box into a hub, and plugging the cable modem into 
same.  This will work, but, as mentioned, Time Warner will charge you an extra $10 per machine if 
you do it this way.

I have come up with an alternative, which I am using (and have been for quite a while)...

The Linux (Redhat 6.0) machine I am using has 2 (3c509) network cards in it.  One of them is 
connected directly to the cable modem, and the other to my internal network.  All internal internet 
traffic is masqueraded through the linux box.  You did not specify whether or not you have a home 
network, but I'm assuming you do.  If not, Just attach the Cable Modem directly to the Linux Box's 
NIC and enable DHCP.

The Roadrunner service provides nameservers, gateway, and your (dynamic) ip address via DHCP.  Just 
config your card to use DHCP and let it rip.  Any machines that are on your internal network 
(Regardless of OS) will need to use the internal IP address of the linux box for a gateway, and 
have Roadrunner's nameservers added to the static DNS list.

In order for the other machines to see the internet, you will have to configure masquerading on the 
linux box.  Masquerading is covered in detail at http://www.rustcorp.com/linux/ipchains/HOWTO.html. 
 Basically you will need to insure you have a recent version of ipchains, and run something like 
the following...

echo 1 > /proc/sys/net/ipv4/ip_forward
ipchains -P forward DENY
ipchains -A forward 192.168.0.0/24 0.0.0.0 -j MASQ

NOTE: This can really mess up any security you may currently have on your system, please read the 
howto...

Also of note:  One of the previous responses listed the Linux Router Project.  You might look at 
Coyote instead.  It is based on the linux-router project, but designed with cable modems and DSL in 
mind. Can be found at Coyote Linux at http://www.vortech.net/coyote/   (Almost) no configuration 
required.  I set it up to play with, Took a grand total of about 5 min. to get it working 
correctly.  Even has a way to get around Roadrunner's propriatary login system to control your 
account. 
Hope this helps, I really don't know of any online guides for this (since it not supported by Time 
Warner...)
Chris Midkiff
cmidkiff@kc.rr.com
cmidkiff@ladybaltimore.com