I travel all over the world since I retired from SmoothWall. 
NYCWireless.net in New York has a captive page for login on dhcp, Cometa 
  in McDonalds (free wireless now with a breakfast in every NYC 
McDonalds that is equipped or $3 an hr), again captive page.

It's entirely sensible. What Monowall should have is a SEPERATE 
firewalled DHCP range anyway with a captive page, if it did its very 
very very cool.

You have my support and I will also donate wireless gear to help too as 
much as you need. I have recently been working with Sputnik 
(www.sputnik.com) and I have one of their APs thats $180 and does 
exactly what we are talking about.

Richard