wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.1-1.el5.rf.i386.rpm

rpm -Uhv rpmforge-release-0.5.1-1.el5.rf.i386.rpm
64 bit
wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.1-1.el5.rf.x86_64.rpm
rpm -Uhv rpmforge-release-0.5.1-1.el5.rf.x86_64.rpm
or download it from http://rpmrepo.org/RPMforge/Using
yum update
yum install phpmyadmin
Remote access setting:
vi /etc/httpd/conf.d/phpmyadmin.conf
<Directory "/usr/share/phpmyadmin">
  Order Deny,Allow
  Deny from all
  Allow from 127.0.0.1
</Directory>
nano /usr/share/phpmyadmin/config.inc.php
find a line
$cfg['blowfish_secret'] = ''; /* YOU MUST FILL IN THIS
FOR
COOKIE AUTH! */
and change it to
$cfg['blowfish_secret'] = 'Everest01'; /* YOU MUST FILL IN THIS
FOR
COOKIE AUTH! */
service httpd restart

Ref:  http://www.khattam.info/howto-install-phpmyadmin-in-centos-5-2010-09-25.html
      http://tecadmin.net/how-to-install-phpmyadmin-on-centos-using-yum/
Ubuntu
Install
sudo apt-get install phpmyadmin
During the installation, phpMyAdmin will walk you through a basic configuration. Once the process starts up, follow these steps:
    • Select Apache2 for the server

    • Choose YES when asked about whether to Configure the database for phpmyadmin with dbconfig-common

    • Enter your MySQL password when prompted

  • Enter the password that you want to use to log into phpmyadmin
 After the installation has completed, add phpmyadmin to the apache configuration.
sudo nano /etc/apache2/apache2.conf
 Add the phpmyadmin config to the file.
Include /etc/phpmyadmin/apache.conf
 Restart apache:
sudo service apache2 restart
You can then access phpmyadmin by going to youripaddress/phpmyadmin.

Ref: https://www.digitalocean.com/community/articles/how-to-install-and-secure-phpmyadmin-on-ubuntu-12-04