AWStats Log Analyzer
ISC dhcpd leases usage analysis
Snare Enterprise: bit.ly/Snare-Trial
Open Source SIEM
A multi-platform universal log collector and forwarder
Free Syslog Server for Windows with a graphical user interface
Visual Syslog Server for Windows with a graphical user interface.
Piwik - Remixed!
Over 600 classes for Web, RFC & File Management
Logs IP to IP contact, number of packets, bytes.