Red Hat Enteprise Linux (RHEL) 4 is loosely based on Fedora Core 2 and 3.
The docs for RHEL 4 are available at
http://www.redhat.com/docs/manuals/enterprise/. For the most part, the info
there is relevant to FC2 and 3 and will probably me mostly relevant for FC 4
when it comes out.
Thomas