Lenovo has released the ThinkPad W700, a WiMax enabled laptop. Sprint is pushing Xohm, their WiMax unit heavily as the next big thing: a mobile broadband network. Not nationwide yet, but Lenovo is hoping it will be, with HP, Dell and Acer quickly following. The network is currently running in Baltimore with plans to expand into Washington and Chicago. Speeds are fast enough for VoIP and the cost is about the same as the cellular broadband service, at $30 per month. Is Xohm the next big thing? We’ll see…