Information on the Iridium system is available here . Globalstar, another Big LEO satellite system, is in commercial service but with a decidedly non-global coverage area. They're also severely lacking in customers. More information on Globalstar's progress is here . Little LEO satellite company Orbcomm has completed their bankruptcy and have been sold at auction.
Information related to their satellite constellation is available here .
Encryption systems employed in cellular and PCS mobile telephone systems are providing relatively easy to crack. More information can be found in the Cellular and PCS pages. As Joe Bob Briggs would say, check it out.