centos6 yum install elasticsearch

Download adn install the Public Signing Key

rpm --import http://packages.elasticsearch.org/GPG-KEY-elasticsearch

Add the following in your /etc/yum.repos.d/ directory in a file named (for example) elasticsearch.repo

[elasticsearch-1.2]
name=Elasticsearch repository for 1.2.x packages
baseurl=http://packages.elasticsearch.org/elasticsearch/1.2/centos
gpgcheck=1
gpgkey=http://packages.elasticsearch.org/GPG-KEY-elasticsearch
enabled=1

And your repository is ready for use. You can install it with

yum -y install elasticsearch