On the ground: Satellite phones
Boeing announced yesterday that they will build 3 satellites for a new satellite based service by company MSV. The satellites should be launched in 2009 and 2010 and will provide a new commercial satellite based cell phone service.
Satellite phones have always had the big disadvantages of requiring bulky hardware and being very expensive. But the big plus is that these phones will truly work everywhere, at least as long as you have a satellite overhead. In the past, various companies tried to offer commercial satellite phone services, but all had limited success, many not surviving. With technology advances however, maybe this one will be another story.