At the heart of the 2007 Kite refresh is the RS690T chipset -- a low-power version of the RS690 chipset found on the desktop. Graphics are provided by a Radeon X700 derivative core; system IO functionality revolves around the SB700 southbridge.
That'll also be coupled with 65nm Turions, giving a significant reduction in power from the current 90nm chips. On some models of machines, that boost will give an extra hour of battery life. The new Turion platforms also rely on the more power-efficient DDR2, and perhaps coupled with SSDs and low-power GPU cores we may see that 5 hours get closer to 6. Definitely worth paying attention to.