This program loads onto of Coova, on top of DD-WRT, on Linux, on the router. errr, wow. Well, it holds everything and auth's if I could ever get it working.

I think this is it. A firmware that connects to a hosted community. Offers a number of authentication tools including Facebook - wow.

http://coova.org/wiki/index.php/CoovaAP/Facebook

A walk through of setting up a chili hotspot / authenticated network. This is money.

Upgrade to the wireless firmware installed on Linksys routers.

More info on general router config