Distributed Logging: Syslog-ng & Splunk - igvita.com
http://www.igvita.com/2008/10/22/distributed-logging-syslog-ng-splunk/

stream live logs from your Ruby, Haproxy, and Nginx processes into your Splunk database for easy debugging and profiling. Of course, same procedures apply to any other process on a remote server - make it log to syslog, and you can route it to Splunk!