A Friendly Warning
It's pretty obvious that various XOHM WiMax networks are operational even if they haven't been officially announced yet. (See XOHM on the Air.) Sprint folks are aware that people are checking the network out but say that you shouldn't get used to it: The networks will be taken down periodically for maintenance and tests.
Sunny Baltimore is the only official XOHM launch so far. (See Sprint's 50 Buck Chuck.)
— Dan Jones, Site Editor, Unstrung