As of yesterday afternoon European time, you can buy the Intel Core 2 Duo E8400 45nm Penryn core. This CPU works at 3.0GHZ and has two cores with a total of 6MB cache memory.
Newegg and Zipzoomfly have them in stock and Zipzoomfly is just over a dollar cheaper. The price of this product is unbelievably good, and we are sure that this dual core will overclock easily to over 4GHz and maybe even significantly more.
At the same time, Intel decided not to sample these CPUs for the time being, as it wants to focus all its PR power on the soon-to-be-launched Skulltrail dual chip quad core platform.
You can buy an E8400 here or here.