The folks at Boingo Wireless play their own game of Katamari Damacy [1], rolling up hundreds of disparate Wi-Fi hotspot networks and tens of thousands of hotspots around the world into one flat-priced footprint. They have now enhanced support for Mac users with a lightweight application - GoBoingo [2] - that's designed to make it easier to connect to hotspots that are part of their network.
Before the GoBoingo client was released officially, you could sign up for a Boingo account and at most hotspots in the company's network enter your credentials manually. I have subscribed to Boingo most recently since January 2008, and have used dozens of hotspots in that more tedious method. (Typically, you have to look for a partner link on the main gateway page for a hotspot, select Boingo, and then enter your user name and password.)
GoBoingo has no user interface as such. Once installed, it runs in the background, and alerts you when a Boingo partner network is in the vicinity. You then enter your login details - if you haven't connected before - and you're informed about cost if your plan requires a payment.
Boingo has two recurring unlimited service options: $22 per month for about 60,000 hotspots in the United States, or $39 per month for about 100,000 hotspots worldwide. The company requires no contract. With a Boingo account, you can also purchase 24-hour passes to the network for $8, and have it billed to whatever credit card is associated with your Boingo account.
Readers with long memories will recall that Boingo had a slightly more complicated Macintosh client a few years ago (see "Boingo for Macintosh Launches [3]," 2005-01-10). That software apparently continued to work through Mac OS X 10.4 Tiger, but didn't function under 10.5 Leopard.
[1]: http://en.wikipedia.org/wiki/Katamari_Damacy
[2]: http://www.boingo.com/download.html
[3]: http://db.tidbits.com/article/7946