Fedora Core is going to be the base for future RHEL releases. Fedora Core 2 Test 2 is currently the best available distribution for SE Linux, it has an option in the GUI installer for installing SE Linux (default is "on" for this release, maybe something different for the next test release), and the policy supports all the most common tasks you will want to perform.
To achieve your goals of generally learning about Red Hat and SE Linux your best option is to just download some ISOs of FC2T2. There are no plans of integrating SE Linux into RHEL 3 as well as it is integrated into Fedora, and RHEL 4 will be longer than you want to wait.
--------------------------------------------------- Bill McCarty, Ph.D. Professor of Information Technology Azusa Pacific University