The latest processor of Intel Core i7 has got 4 cores. Each core contains 2 threads which allows you to optimize your processor with the latest software which requires multithreading.

Yes, what Michael said. The core I7 has 4 cores, but it uses a feature called hyper threading which allows the processor to compute two bits at a time, per core, so it effectively has 8 cores and this is what you will see in any CPU core monitoring utilities such as that found in the task manager.
Hope this helps.

thanks it really helps!

yes but there latest processor i7-970 got 6 cores .... for details go to
http://www.intel.com/products/processor/corei7/specifications.htm