I have an unlocked Nexus One with a pre-release of Android 2.2 “Froyo”, and I have a T-Mobile mobile data plan from Google; I imagine that, like most big companies, we get a pretty good deal on it. As of now, I’m never paying for Internet in a hotel or airport again.
You can turn the Nexus One into a WiFi hotspot is a matter of a couple of clicks. It turns out that other Android phones like the Evo and the Droid X offer this capability, but because they’re sold through and locked by the network operator, you have to pay extra for it. Similarly for modern iPhones. For a heavy traveller, the amount you pay extra may well be less than you’re currently paying some combination of hotels and Boingo or equivalent.
But if you get an unlocked phone, the network operator would have to go to considerable extra work to detect that you’re doing this and prevent it. An unlocked modern phone will run you something in the $5-600 range. But you know, if you’re a heavy traveler who’s been paying for Internet several times per month, maybe that’s cheap.