Need calendar for web site

Our organization has multiple local societies, all of whom have monthly meetings featuring speakers and they also host special events. we think a calendar listing ALL the events of the local societies would promote members visitng other societies' events.

We'd like calendar updating to be available to only a few people, but the results available on the web for all.

The web site does have a forum, and I understand there may be additions to the forum software to facilitate a calendar.

Any guidance would be appreciated.

PS...what tool is used for the calendar on this BBS?

 

Thanks Arie.