Next-generation iPhones likely to focus on internal improvements.
IBM Announces the (long rumored) PowerPC 970MP
Each core has 1MB L2 cache
One core can be swiched off for low power mode
Also low power 970FX processors were described:
1.2GHz at 13W
1.4GHz at 13W
1.6GHz at 16W
An official press release can be found (Japanese).
970MP based PowerMacs have been expected for later this year. Despite Apple's recent announcement for plans to switch to Intel based Macs, at least one or two more PowerPC based PowerMacs are due before the switch.