All -
Red Hat Enterprise Linux (RHEL) 4 was mostly built from Fedora Core 2 and Fedora Core 3. Obviously, RHEL 4 and FC2/3 are not identical, but they share very similar application and configuration sets.
Now that RHEL 4 is released, the documentation for it is available at http://www.redhat.com/docs/manuals/enterprise/. These docs are pretty awesome, and probably more relevant to Fedora Core than any other set of docs on the 'Net.
Just posting this in the hope that it is helpful.
Thomas