Now if there ever was a company working on world domination, it would be FON. They aim to build a global network of Wifi hotspots by selling subsidized routers that have custom firmware. The routers have a private secure WPA based network for you to use, and a public network that has a signup page, for anyone else to use. There is also a control that limits how much bandwidth the public can use. They have a few hundred thousand users, and are now the largest WiFi network by far, but the location of their base stations is much more random and less useful than T-Mobile HotSpots.
The incentive in the short term is that you can get a high quality router at a very low price. FON has been giving routers away to seed markets and to surround Starbucks stores. The incentive in the longer term is that if you have a FON router at home, you can use any FON router you find on your travels for free.
I've had a FON router for some time. I met CEO Martin Varsavsky when he gave a talk at eBay last year, and got one of the initial Linksys units with custom firmware. When their own hardware solution came out it had a much nicer feature set, so I upgraded to La Fonera as they call it. I've been using it as my primary home router for about six months now, and its an excellent design. Its been much more reliable than the other low cost routers I've owned (Netgear and Linksys) and works as well as the much more expensive Apple Airport Express that I've had for a long time.
FON just released a booster antenna "La Fontenna", it is designed to give 6.5dB of extra signal strength and project further out than the standard antenna. The idea is that you mount it on the window facing the street, and it covers a larger area. I just got one, and while it seems to work fine, it doesn't appear to be giving me as much signal strength or range as I expected. I wandered around outside with my MacBook using iStumbler's WiFi monitoring widget to track signal strength, and it showed a bit more gain than my Airport. I think I need to experiment a bit more with positioning La Fontenna.
So next time you need a router, don't just buy a normal one, join Fon and support world domination!