T*Mobile (The Deutche Telekom-ified mobile network provider formerly known as Voicestream, formerly known as Omnipoint, formerly known as...) is rolling out 802.11b access in urban areas throughout the country. At the moment, the connectivity is mostly through Starbucks, which makes it rather easy to find a hotspot. Borders will soon follow suit.
The plan isn't exactly cheap: $30/month for unlimited wireless access in a single urban region, $50/month for unlimited nationwide usage, and various pay-as-you-go plans. (It's just a cunning way to get people to pay for yet another ISP/Mobile telecom service plan every month.)
I've been considering it recently. I'd certainly prefer a community wireless network, but it's not like my access point 10 miles away from DC is useful for very many people. I'm in downtown DC about two days per week at the moment, without a permanent office or steady pipe. (CyberSTOP on 17th is nice, but a little smoky, out of the way and small.)
I would sign up a local service plan on an whim, if T*Mobile would only deign to offer the local plan in DC. Sigh.