Anyone ever heard of this company? This is not to be confused with the eKit/Telestial offer.
I'm sure most people in the big cities in the US are familiar with the 'unlimited wars' that have been going on over the past few years now, usually amongst CDMA & iDen operators, but now comes a couple companies doing unlimited for GSM (with one of them offering an OK data offer): Simple Mobile (and AirVoice for voice & text on the AT&T network). Simple Mobile resells T-Mobile service (even their 3G coverage is claimed to be operational) so this may be an option at least for extended-duration travellers to the US. Basically you pay 50 or 60 $/month and get unlimited talk, global (!) text, as well as 50 or 150 MB of data, depending on which option you pick.
It is a prepaid offer so you have to reload your account at least every 30 days. At present, finding reloads for this company can be a bit difficult but it supposedly is getting easier every month. They have been around in my market since roughly November 2009, I believe.
Remember coverage is limited to T-Mobile's native network (should be both 2G & 3G now) and has no roaming at all.
Their URL is
OMG! Simple Mobile