As a few of you know, I'm doing a fair bit with WRT54G routers atm. These little routers are cool. They run Linux as their main core, and can be customised beyond belief. I'll be posting some of my scripts etc over the next few weeks to turn these things into a captive portal with an authorised access setting - great for groups like Melbourne Wireless folks.
As an example, if you're not registered via MAC address on my AP, and you try to bring up any web site, you get this page. I'll write up a how-to on this soon and post it. Until then, feel free to contribute ideas!