devialog is a behavior/anomaly-based syslog intrusion detection system which detects unknown attacks via anomalies in syslog. It can generate signatures for ease of management, act upon anomalies in a predefined fashion or perform as a standard log parser
Syslog2db, Syslog to Database, is a log parser that inserts log entries into databases through the PERL DBI and DBD interfaces. In its current beta form, it takes advantage of syslog-ng's ability to format the output of its syslog entries.