The latest up2date AFAIK is up2date-2.8.40-2.7.2, and you can still find it in the update dir at RHL mirrors or search rpmfind. Be aware RHN support is closed for RHL 7.x and 8.x series as they where EOL'ed 2003/12. RHL 9.x will follow 2004/04.
If you want to/need to support RHL boxen you can:
- turn to the Fedora Core Legacy project,
- run Fedora Core,
- run cAos,
- upgrade, patch and build your own rpm's from source.
If you want to move on but can't let go of rpm's and RH(E)L you can:
- run CentOS,
- run Tao Linux,
- run White Box Linux,
- run any other popular rpm based distro,
- buy RHEL.
So there's a lot in the spectrum between buying and DYI, all depending on your skills and the need for support. Mind you, upgrading, patching and building your own rpm's from source is good for only OpenSSH and openSSL, but otherwise you better damn well know what you're doing. Not to discourage you, but there's too much vulnerabilities to keep track of if you have to do it all by yourself.
I recently migrated one server to CentOS for trials, and so far it's been running w/o probs.