MojoCat

I am trying to get a basic blueprint of the following project: Simular to air2data, I would like to allow wireless data in each of my store's networks. The user would connect to the wireless network where he/she would be presented a webpage to login. After a successful login, the user would have access to the network/internet. I am guessing I would start out with a redirect until the user starts a session - perhaps stored under the mac address of the computer. I think the router would point to the webserver as its default gateway, where the webserver would authenticate the user. Anyone ever had a project like this? I know my way around PHP quite well, but its just finding the structure of this project that is taking a while to figure out. Any ideas would be greatly helpful! Dan