The LED screen technology is available on the 15" models only. The 17" models still use LCD screen technology. From the Apple web site:
More than beautiful
The new 15-inch MacBook Pro is better for the environment, thanks to its new mercury-free display. Backlit by light emitting diodes (LEDs), the display weighs less and is more power efficient than the cold cathode fluorescent lamps (CCFLs) which most notebooks employ, and provides full brightness immediately after the system is turned on.
My current system is an MBP C2D 17" that I bought about 6 months ago. I would need to see one of the new systems "live and in person" with the HD 17" inch screen before upgrading.