rpm --import http://passenger.stealthymonkeys.com/RPM-GPG-KEY-stealthymonkeys.ascrpm -Uvh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
Install the passenger-release package from the main repository.
Fedora Core 17:
yum install http://passenger.stealthymonkeys.com/fedora/17/passenger-release.noarch.rpm
Fedora Core 16:
yum install http://passenger.stealthymonkeys.com/fedora/16/passenger-release.noarch.rpm
Fedora Core 15:
yum install http://passenger.stealthymonkeys.com/fedora/15/passenger-release.noarch.rpm
Fedora Core 14:
yum install http://passenger.stealthymonkeys.com/fedora/14/passenger-release.noarch.rpm
RHEL 6 / CentOS 6 / ScientificLinux 6: (Note: these packages depend on EPEL.)
yum install http://passenger.stealthymonkeys.com/rhel/6/passenger-release.noarch.rpm
RHEL 5 / CentOS 5 / ScientificLinux 5: (Note: these packages depend on EPEL.)
rpm -Uvh http://passenger.stealthymonkeys.com/rhel/5/passenger-release.noarch.rpm
From there you can use YUM to install packages. For example, try one of these:
Phusion Passenger for Apache:
yum install mod_passenger
Phusion Passenger for Nginx:
yum install nginx-passenger
Phusion Passenger Standalone:
yum install passenger-standalone