Intel's aggressive advancement of their processor technology has made it difficult for the casual onlooker to keep up.
Intel first introduced their current Core microarchitecture in Q1 2006. This represented a significant leap forward over their previous Pentium M microarchitecture. Apple took advantage of this transition and delivered some of their first Intel Macs using the Core-based processors. The Core microarchitecture spawned many processor revisions which were known by their code names: Merom, Conroe, Woodcrest, and Penryn. Many of these processors have been used in Apple's Macs over the past 2 years.
On Tuesday, Intel provided the first official information about the Nehalem microarchitecture -- the successor to the Core microarchitecture. Intel plans on phasing out the Core microarchitecture starting in late 2008 with the introduction of Nehalem-based server processors. Laptop and desktop processors based on Nehalem are not expected until 2009.
http://www.macrumors.com/2008/03/19/intel-outlines-next-generation-processors-nehalem-due-in-late-2008/