According to a company called
Truphone, they have unlocked the secret of IP telephony on the iPhone, and
demonstrated said ability today at DEMOfall 07 in San Diego. Executing commands
via the Terminal (i.e., on a phone which had been Jailbreak-ed), Truphone CEO
James Tagg was able to call another mobile phone using only an IP connection --
all without breaking the SIM lock. According to the company, the software is
still in beta, but they soon plan to have a version which will simplify
activation, and allow seamless switching between WiFi and SIM use. Clearly, an
exciting development for iPhone users, but a cringe-inducing situation for AT&T.