Trying to find a calendar/PM tool with specific requirements

[swimgeek]

Hi,
I'm trying to setup a scheduler/Project Management tool for the research equipment in our lab. Any web based calendar would probably do, except that we have a restriction: a request for a resource submitted by a researcher can be overridden by an administrator. Also anyone interested in an event should receive an email about it, as it is updated. The tool should also be web-based. Anyone know about any such calendar/PM tool? I'm also willing to do some programming to modify an existing tool to achieve the requisite functionality.

thanks a lot!

[aja]

Try tutos:
http://www.tutos.org/homepage/index.html