Oak is a program that can be used to monitor syslogs from a collection
of servers and notify operators when problem conditions arise.  In
addition to providing immediate notification of critical problems oak
will also batch less critical problems into summary messages that can
be sent less often and via any medium.  For example you may wish to
have oak page you on critical events while sending a summary of less
important messages to your terminal once an hour.  In addition you
could send a daily email message summarizing all events.

WWW: http://www.ktools.org/oak/