In an interview with Forbes recently, CEO of ST-Ericsson says that the device mobile Windows Phone 7 from Nokia will wear the U8500 dual-core processor which in future generations will also be used on mobile Windows Phone 7. This also put Chip U8500 GPU that's great that Mali-400 as mounted on the Samsung Galaxy S I9100 II.
Phone Windows Phone 7 will wear the U8500 dual-core chipset running at 1.2 GHz. This might still change but if later this device could be so slid then these gadgets will become the Windows Phone 7 smartphone with dual-core processors.