How could I monitor URL access by users and email myself when someone accesses a particular URL? I would need to know which host had accessed that URL and the time of access.

You can use web-proxy for url.

oh but how run webproxy

Is there any way to use web-proxy with SNAT enabled on concerned IP Pool..?

i was create a webproxy+hotspot+user-manager,
where i can see the live url monitoring for each user/client?
i only see the ip address not the url. can you help me?