Because CentOS doesn’t pull all dependencies correctly, here is my little memory hook for installing phpmyadmin (and mysql, of course)
rpm -Uvh http://apt.sw.be/redhat/el5/en/i386/RPMS.dag/rpmforge-release-0.3.6-1.el5.rf.i386.rpm yum install php phpmyadmin php-mcrypt php-mbstring mysql-server
After installing the packages, edit
/etc/httpd/conf.d/phpmyadmin.conf and add the IP of your admin workstation to the line that begins with Allow from.
For using phpmyadmin with cookie auth, you have to set a blowfish secret in
[...] $cfg['blowfish_secret'] = 'Secret_Password'; [...]