Under RHEL 4, I use a repository I found a while ago along with a wonderful package manager. Apt blows Yum out of the water and should immediately replace it.
The many features just makes it a must have for any distribution that supports it, and if it doesn't, they need to get their priorities straight.

I failed to find an installation source for RHEL 4 in your tutorial, just 3. So, I will tell anyone who needs it to find it at the link at the bottom of this reply.

Oh, just make sure you get a good package manager. It's just as important as getting apt itself. I also left a link to get the manager I use, Synaptic.

For apt RHEL X (and Fedora X):


For Synaptic: