I'm in Silicon Valley. We used to have the Ricochet wireless service, which allowed one to work while mobile (i.e., actually moving). It was sort of like a cell system, and would hand you off between sites. A friend who commuted on the train between San Jose and San Francisco used it, but found that he couldn't keep a steady connection. It was better suited for off-line composition, and a quick connect-and-send when the train pulled into a station. Unfortunately, that service never figured out how to pay for itself, and folded.

I'm wireless at home, and my favorite local coffee shop is wireless. I usually works great, though some portable (not cell!) phones share the same frequency band as 802.11(b). I can tell when my neighbor is on the phone because my service degrades.

Friends who travel have ponied up the bucks to use the wireless services that Starbucks provides, since there are Starbucks everywhere. They're generally happy with it, since it lets them connect from most major airports.

I have two friends who try to connect through their cellphones, but they usually fall back onto something that actually works.

I don't know anyone who does any serious connectivity with anything smaller than a laptop. I occassionally see someone with a wired iPaq, but that's rare.