Shipments of these processor will start in Q4 2007, so it's possible that some people will be able to get their hands on these chips before the year ends.
In Q1 2008 we'll see the dual-core Wolfdale whic has a 1333MHz FSB and 6MB cache memory. It also has Intel VIIV, vPRO, Intel VT, Intel TXT, HT, SpeedStep, 64-bit and execute disable bit. It uses the Socket 775 but will require a new chipset.
The quad-core version is codenamed Yorkfield and will run at a 1066MHz FSB with 12MB cache memory. The Yorkfield isn't a native quad-core processor, it's basically two Wolfdale processors stitched together.