# centos 5 32bit
rpm -Uvh http://yum.postgresql.org/9.1/redhat/rhel-5-i386/pgdg-centos91-9.1-4.noarch.rpm
yum install postgresql91-server
/etc/init.d/postgresql-9.1 initdb
service postgresql-9.1 start
chkconfig postgresql-9.1 on