Disclaimer: I've known these guys for a long time and am pals with them, so I waited until someone else (in this case Grant at NewsForge and the NYT) put something up independently about them before linking to them.
LinuxCare founders Dave Sifry, Art Tyde and Dave LaDuke have started their second company: Sputnik
. Basically, they have an ISO you can download that will turn a laptop with an 802.11b card into a wireless gateway. They also wrote a user-authentication scheme that reroutes all traffic to the gateway until the user logs in via a web form. This should sound familiar to people who stay in broadband capable hotels a lot. Using this authentication technique, the software allows you to choose who can and cannot use your gateway, and in you'll be able to charge strangers for access (with Sputnik handling the billing). This will likely get some isps a wee bit upset. NewsForge
has an article
detailing what they are doing. Update
: Turns out the authentication wasn't written by Sputnik, my bad. They use NoCatAuth