Howtoforge posted a guide about installing Rsyslog 5.7.x on CentOS 5.x

This tutorial shows how you can install new generation of syslog servers by using Rsyslog. According to Rsyslog web site (www.rsyslog.com), Rsyslog is an enhanced syslogd supporting, among others, MySQL, PostgreSQL, failover log destinations, syslog/tcp, fine grain output format control, high precision timestamps, queued operations and the ability to filter on any message part. It is quite compatible to stock sysklogd and can be used as a drop-in replacement. Its advanced features make it suitable for enterprise-class, encryption protected syslog relay chains while at the same time being very easy to setup for the novice user.

  Installing Full-Featured Rsyslog 5.7.x On CentOS 5.x