Ah, Boingo just keeps getting sweeter. After showing off its mobile service and partnering with FON, now the WiFi operator is making it even cheaper to hop online via its worldwide hotspot network. The company has announced that it will be hitting us up with a flat-rate service for $39 per month, which will enable users to utilize "more than 100,000 WiFi hotspots" across the globe sans roaming charges. Of course, this won't impact those Boingo users who manage to stay within the confines of the US of A, but globetrotters will certainly appreciate the end of per-minute roaming charges when surfing abroad. [Warning: read link requires subscription]