Have a look at SolarWinds Kiwi syslog server. They have both free and paid versions. The free version limits you to only 5 sources though.
http://www.solarwinds.com/free-tools/kiwi-free-syslog-server
Another good free option is PRTG. It will monitor up to 100 sensors in the free version.
https://www.paessler.com/free_syslog_server