The majority of the CPUs are expected to be quad-core Xeons, with only a few being dual-core. As the article mentions, this could be Intel getting ready to steal AMD's thunder when Barcelona arrives:
Of the 12 chips, nine will fall into the Quad Core Xeon 5400 series (Harpertown), while the other three will be in the Dual Core Xeon 5200 series (Wolfdale). From the lineup, it looks like Intel is trying to make sure it fields a full team of quad-core products to face off against Barcelona going into next year.
Some of the quad core CPUs will reach all the way up to 3.16GHz, and the dual cores up to 3.4GHz. There is not an official statement from Intel yet, but it will be very cool to see 45nm CPUs begin making their way into the market.