Migrating from IPChains to Netfilters?

lodn asks: "I've been using a Linux gateway for some time now. It's a simple kernel 2.2.18 install with IP forwarding. Thanks to the great HOWTO on IPchains I was able to configure it with no problems. Now I'd like to upgrade to kernel 2.4, however I have not been able to find a HOWTO for Netfilters! Does anyone know where such can be found?" Anyone know of any IPchain-to-Netfilter migration utilities? I must admit, I haven't been able to find much information about Netfilter usage either when I went looking into 2.4, however my firewall is also still 2.2. Time to upgrade, methinks.