install mysql and phpmyadmin via yum

1. install mysql and mysql-server
# yum install mysql mysql-server

2. start mysql server
# service mysqld start

3. change mysql root password
# mysqladmin ping -u root -p'' password 'newpassword'
Enter password: your-root-mysql-adminpasswd-here
mysqld is alive

4. install rpmforge
refer to: http://wiki.centos.org/AdditionalResources/Repositories/RPMForge

5.  yum install phpmyadmin

6. modify config.inc.php
# vim /usr/share/phpmyadmin/config.inc.php
$cfg['blowfish_secret'] = 'any-string-you wants for encryption';

7. modify phpmyadmin.conf
# vim /etc/httpd/conf.d/phpmyadmin.conf
replace "Allow from 127.0.0.1" to "Allow from all"
(Note: It allow any client login to your phpmyadmin)

8. restart Apache
# service httpd restart

9. open browser "http://server/phpmyadmin
login with root/your-root-mysql-adminpasswd-here

reference:
http://www.linuxforums.org/forum/red-hat-fedora-linux/57941-how-install-phpmyadmin-via-yum.html
http://www.shocr.com/yum-install-phpmyadmin/
http://www.cyberciti.biz/faq/mysql-change-root-password/