I got too much problem in installing php-mcrypt using epel-release-6-8.noarch.rpm. It has some dependency problem.
Then I tried in different way.
Get the php-mcrypt using "wget ftp://ftp.univie.ac.at/systems/linux/fedora/epel/6/x86_64/php-mcrypt-5.3.3-3.el6.x86_64.rpm" command.
Then install libmcrypt
The installed php-mcrypt using following command
yum install php-mcrypt-5.3.3-3.el6.x86_64.rpm