ZER01 (http://www.zer01mobile.com/) is an upcoming AT&T MVNO that will be providing unlimited data, and unlimited VOIP.

Currently, they're doing some sort of VOIP that they only support on WinMo phones, but if they port it to other platforms (Symbian, Android, Maemo), or if it's just SIP but they haven't verified it with anything than WinMo ... I wonder what people's thoughts about about the potential of using them as a WWAN data carrier for the Maemo 5 device (with or without their VOIP voice support).