With AMD and Intel backing the boat, multi-core architectures have really taken off and gotten a lot of press the past year or so. A lot of people are still confused as to what dual-core entails, how long it has been around, the differences between dual core and SMP, and many other things. There is an excellent article at realworldtech
covering exactly this that describes the relationship between dual core and their single core brethren. The article also goes over the major architectures and how they implement it. There isn't a lot of geek-speak and it's only a few pages, but is still geared towards having specific information. If you are interested in learning a bit about multicore tech I suggest you take a look.