While you can give anyone access to Event Clipboard, there are no public pages. By that I mean...in order to get access to the calendar of events you have stored in Event Clipboard, you have to log in. Event Clipboard definitely won't suit your needs for public outreach. It's sole purpose is to help you organize your internal operations and keep your staff and vendors on the same page.
That said, If you're looking to advertise your events:
Check out
http://www.masterplanneronline.com/losangeles/. I'm not sure what membership costs at Masterplanner, but that gives you a fairly good outlet if not a wide ranging market. If you'd like to create individual registration pages, you might want to check out
http://www.regonline.com/. I've heard good things about that software.
Yahoo calendar might also have public access. I'm sure Google calendar does. check it out here
http://www.google.com/intl/en/googlecalendar/tour.html. Then you can link directly from your website to your Google calendar. I think it might also be free.
If you're looking for something custom for your website, that's another matter all together. Email me at
support@integratechange.com and we can talk about options.
Hope that helps.
-Chris