Asked Wednesday about his company's exclusive relationship with AT&T -- cited by some as a barrier to further iPhone penetration -- Apple interim chief Tim Cook responded by praising the carrier as 'the best wireless provider in the US,' explaining that its GSM foundation gels with Apple's goal of providing 'one phone for the entire world' while rival CDMA technology 'doesn't really have a life to it.'

Apple happy with AT&T, indicates no plans for CDMA iPhone