Monitoring WIFI Network for Malicious Use

[infolookup at gmail.com (infolookup at gmail.com)]

Hello All,

I would like to know how are other out there monitoring there WIFI network for miss use or malicious access.

Our WIFI setup is now being developed and we are now trying to see how we can keep and eye out for miss use while not 
making things too difficult for our users.

Current setup -->Cisco Wireless controller--> several cisco AP's

SSID: Public(limited LAN access) authentication--> Open

SSID: Private Authentication WPA2

As of right now we will we have the public wifi lan open but hidden SSID, I know it can be sniffed via Kismet or 
anything like that, but we can't change the Open as yet since its now in a learning state.


So my real question is what can we do to monitor the LAN this way if we know that no users are there after 7 pm and 
there is access then its not allowed.

Thanks,
Sent from my Verizon Wireless BlackBerry