Calendar - Post Events

We need a page containing a calendar. The users should be able to post an "Event" with the info; title, date, description. However, the admin should be able to approve the Event before being published on the site. Also be able to activate/de-activate Events. The Events should show up in the calendar under the correct date. Should be a very simple job! This calendar should be implemented to an OSCommerce site, so php coding is necessary.