All great news!
Well looking at Intel's Roadmap
http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2554
iBook (Rev.A)
773 Dothan (Ultra Low Voltage) - Single-core 1.3Ghz, 400Mhz FSB
iBook (Rev.B)
??? Yonah (Ultra Low Voltage) - Dual-core 1.06Ghz, 533Mhz FSB
x38 Yonah (Low Voltage) - Dual-core 1.5Ghz, 667Mhz FSB
PowerBooks (Rev.A)
x48 Yonah (Low Voltage) - Dual-core 1.66Ghz, 667Mhz FSB
x40 Yonah - Dual-core 2Ghz, 667Mhz FSB
x50 Yonah - Dual-core 2.16Ghz, 667Mhz FSB
PowerBooks (Rev. B)
x58 Yonah (Low Voltage) - Dual-core 1.83Ghz, 667Mhz FSB
x60 Yonah - Dual-core 2.33Ghz, 667Mhz FSB
And a Merom based PB!
Mac Mini (Rev.A)
756 Yonah - Single-core 1.66Ghz, 667Mhz FSB
Mac Mini (Rev. B)
766 Yonah - Single-core 1.83Ghz, 667Mhz FSB
x48 Yonah (Low Voltage) - Dual-core 1.66Ghz, 667Mhz FSB
That should give the Powerbook a badly needed boost against the iBook and give the Mac Mini enough power to make it a decent buy.
The iBook will be promoted as an ultra-portable while the Powerbook will satisfy power hungry users.