I checked RHN - Channels - Easy ISOs for the updated images. I see theThey are were you were looking. Just click on the base channel (e.g. Red Hat Enterprise Linux ES (v. 3 for x86)) and you'll find them.
Beta ISOs listed, but not the released Update 4 images.
Are my old eyes playing tricks on me? Should I just wait impatiently for a few more days?
Kind Regards, Dirk