Users of AT&T or T-Mobile in the U.S. can be safely assured their calls will NOT be publicly wiretapped for AT LEAST a few months. Mainly because security researcher Karsten Nohl will be releasing an open-source, distributed computing project, designed to crack the encryption used by regular GSM-devices on" transmission (also known as "A5/1").
[The whole point of the venture is to spur tele-carriers to improve the security-flaws of their respective service protocols. The bug Nohl is talking about in the link at the end of this post, has been known for over 15 years! So.., covert cellular surveillance has probably been going on for years by now...]
"We're not creating a vulnerability, but publicizing a flaw that is alreay being exploited, very widely", Nohl said in a phone interview.
Utilizing 80 high-performance computers to distribute the workload, will use about 3 months to generate a key-table. But if about 160 people on the Internet were to offer computing-power, it would take half that time to complete. Which is Nohl's vision for the project, and the end-result of this major computational task, is to generate an encryption-key reference-table by use of which will grant anyone the ability to de-crypt cellular transmissions.
It also seems that my own carrier here in Norway (NetCom) uses A5/1, so I'm just as vulnerable as anyone else, except for the unlucky morons who use un-encrypted GSM (does any carrier implement this solution? anyone? :P).