Open Source host, service and network monitoring Web UI
http://www.icinga.org/

Icinga Web is highly dynamic and laid out as a dashboard with tabs which allow
the user to flip between different views that they need at any one time. These
can be customized to suit the users' day-to-day needs as all displays are
persistent and remain when the user returns. With an AJAX search tool, filter
capabilities, and compound commands, the differences to the classic Nagios
interface are plenty.