If you googling you will find any thing you want . :) try this on linux specially www.google.com/linux any way about yum with RHEL4 , it work and compatible with it, download the latest yum from here

http://linux.duke.edu/projects/yum/download/2.6/

Also you want some repos on /etc/yum.repos.d/

paste these lines in the file .
 
This a dag repo for example ya3ny, search another more rhel4 repos

[dag]
name=Dag-RHEL-Yum
baseurl=http://dag.linux.iastate.edu/dag/redhat/el$releasever/en/$basearch/dag
http://www.mirrorservice.org/sites/apt.sw.be/redhat/el$releasever/en/$basearch/dag
http://mirrors.ircam.fr/pub/dag/redhat/el$releasever/en/$basearch/dag
http://apt.sw.be/redhat/el$releasever/en/$basearch/dag
enabled=1
gpgcheck=1 

Then import dag gpg key 

rpm --import http://dag.wieers.com/packages/RPM-GPG-KEY.dag.txt }}}



Redgards, 

Ahmed M. Elsebaey