MacWorld UK says:
Apple has quietly updated its MacBook and MacBook Pro products, migrating these to the new Intel ‘Santa Rosa’ processor.
Information pertaining to the new Macs is currently only available on Apple’s US website, UK pages haven’t yet been updated.
The new MacBook uses the Santa Rosa chipset which boasts a faster 800MHz front side bus over the previous MacBook models which had a 667MHz front side bus.
The graphics processor has also been updated. The new MacBooks field an Intel GMA X3100 graphics processor with 144MB of DDR2 SDRAM shared with main memory. Previous models offered an Intel GMA 950 graphics processor with 64MB of DDR2 SDRAM shared with main memory.
The MacBook Pro can now be configured with an optional 2.6GHz Core 2 Duo for an extra charge.
The new models are available now through Apple’s US store in 2GHz and 2.2GHz (formerly 2.16GHz) speeds.