PHP Calendar with Zip Code search, etc…

So I have a client that is looking at having a calendar page but has certain criteria:

* Calendar with options to select different cities
* Searchable within a certain radius based on a Zip Code searches
* Admin interface to approve posts
* Perhaps a way to charge visitors a fee to post on the site
* Some other features like ease of use for visitors would be nice too.

Is there anything out there like this? He is looking for something basically to have all these different states and cities with listings. I have searched Hot Scripts [dot] com and have found some decent php mods but nothing really that nails what he’s looking for.

Any ideas? I’m almost sure that I’m going to have to write this myself, but trying to avoid that if something already exists:)

I have used the EC3 plugin before but don’t know if that is going to necessarily work for what my client is going work for him. That’s why I asked about this here. I figure with all of the brilliant people here someone may have <i>something</i> I could look into.

Thanks!