Sessions? Cacheing? maybe and Event Gateway?

Hello Everyone,
I am trying to create a page that will list who is currently logged in to my site, kind of like how this message board tells you how many people are viewing it.

I can do this by updating the database with time stamp every time a customer loads a page and then have another program run every 30min to see if the stamp has been updated and log them out if it hasn't. This really isn't a good way of doing it though.

I have been looking into sessions and cacheing as a possability for doing this but I can't figure out how.

I am running ColdFusion 7, any help would be greatly appreciated.

Thanks,
Cursian

Events in application.cfc can be used for this. For example: Add username after login to variable in application scope wich lists logged users. When OnSessionEnd event occurs remove username for session which finished from list. And use list from application scope to display logged users at any time.