You're comparing apples to oranges. Syslog-ng is an advanced syslog daemon that does exactly what you are trying to do (for free). There's also another known as rsyslog which is not as mature, but quite good nonetheless. Splunk (clunk) is a commercial product that is *extremely* expensive once you get above their 500m limit a day.
There's a very good whitepaper on syslog management on Cisco's website - just do a search for "Building Scalable Syslog Management Solutions". Since I am a new member here, I can't post the link