Spiegel has learned from NSA documents this week that the NSA has reportedly succeeded in accessing user data from iOS, Android and Blackberry devices. The report goes on to say that the information they can access includes contact lists, SMS traffic, notes and location information about where a user has been.
The documents also indicate that the NSA has set up specific working groups to deal with each operating system, with the goal of gaining secret access to the data held on the phones.
The tapping of an iPhone requires access to the users PC to install scripts so these users should be almost certainly safe unless you perhaps for for a US company with government links. Blackberry and Android users are more affected with the NSA seemingly have direct external access into those systems despite claims from Blackberry that they have not provided a backdoor for the NSA.
Interestingly Windows Phone users are not indicated as affected here which is ironic as Windows is a notorious system for hackers. So it seems that the once most hacked system is now perhaps the safest mobile OS, for now.