Wireless redirect to local web server?

Here's what I'd like to do as an experiment:
I'd like to have a wireless router connected to a linux box with a web
server. There would be no internet connection on any of it. If anyone
connects to the wireless access point and attempts to go to any page
they get redirected to the internal web server main page. No proxy
settings required, maybe some sort of simple authentication login
eventually. The page can have links but they would stay on that web
server (or maybe go to a second box on the same network).
Can I do this with squid as a transparent proxy and iptables?
Does the web server have to have two nic cards even if the redirect
stays inside the server?
The eventual goal would be a sort of "wireless BBS".