title: Multiuser web-based calendar based on php, mysql, javascript
body: <p>I'm searching for a multiuser web-based calendar system that supports multiple users.
  I'm looking for these features:</p>
  
  <ul>
  <li>Multiple users</li>
  <li>Two user groups: First group is allowed to see events, the second group can create and edit events</li>
  <li>The events should be stored in a mysql database or a file</li>
  <li>The system has to be (very) easy to use. It will be used by non-technical users</li>
  <li>Ideally it should be integrated in wordpress, but thats a nice-to-have</li>
  </ul>
  
  <p>If you know something like this please let me know.</p>
  
  <p><em>edit (concerning the google apps comment):</em>
  the calendar should be hosted on an existing website</p>