http://www.hexus.net/content/item.php?item=4604

The article says that Sossaman, Intel's Yonah-based ULV server CPU, will have EM64T enabled. As a consequence, it's suggested that perhaps Core Duos also have the ability to run x86-64, but it's currently disabled and hidden out of view. While it seems like a wild rumor at this point, consider that a recently launched BIOS revision for dual-core Xeon platforms just unlocked the CPU's ability to perform Virtualization! Sneaky, sneaky Intel...