BSI, the German Federal Office for Information Security, has published a report on "Enterprise mobile device security" (in German*) that provides a comprehensive overview on the current risks associated with the deployment of mobile devices in an enterprise context.
The report... covers Apple iOS, Google Android and Blackberry devices, taking a hard look at the current generation of hardware and software and the resulting dependencies on a limited number of key suppliers.
The study identifies key risk areas associated with the deployment of mobile devices in an enterprise context... and makes the case for doing so only in the context of a well-defined framework of organizational and technical measures that secure the enterprise against industrial espionage and other kinds of attacks.
* An English version may be available. Ask at ESD America.
Audio interview about Cryptophone, a high security cell phone ≈ 6 min.