Depending on the wireless router that you use, you can flash the device to DD-WRT and use it as a hotspot. There is an option already built in to use the AnchorFree software and appears to work similar to what hotels provide: paid service wireless. For a tutorial and how to setup a router that's already flashed to DD-WRT with the AnchorFree service look here: This utilizes two separate routers, one for home setup and the second for the "hosted" wifi.
One of the new features of the DD-WRT v24 firmware is a HotSpot Revenue generator called: AnchorFree. This posts an ad generated in a frame at the top of the browser window, through AnchorFree's network of advertisers. When someone clicks on the ad, the person hosting the router gets a little chunk of change from the click.
Flashing the router depends on the router make and model. Check out the DD-WRT website for more info on that.
If AnchorFree isn't exactly what you are looking for, built in the DD-WRT is also SputNik:
SputnikNet is the super-flexible, web-based management and captive portal authentication system for Wi-Fi hotspots and hotzones. Manage one or thousands of hotspots with SputnikNet. SputnikNet enables you to:
- auto-provision Wi-Fi access points (APs) by plugging them into broadband
- manage Wi-Fi APs centrally, over a secure Web connection
- design captive portals with your brand
- authenticate users and devices for free or paid Wi-Fi
- track usage by access point and Wi-Fi end user
It appears that SputNik might be the closest to what you are looking for. Here is a how to in using sputnik. You can also purchase a sputnik ready device, instead of flashing the router yourself.