Redhat's Emacs maintainer now hosts a yum repository
containing Emacs 23 snapshots for F8, F9 and RHEL5.
Fedora:
http://people.redhat.com/coldwell/emacs/repo/fedora/emacs-release-23-1.fc8.noarch.rpm
RHEL:
http://people.redhat.com/coldwell/emacs/repo/rhel/emacs-release-23-1.el5.noarch.rpm
(This info sent to me by Brad Walker, thank you!)