New Prozessors with 8 cores?

Hey,
I have read about the new Intel Core i7 processors. Have they realy 8 cores? I have found a text, there say the people, that the new processors are 4cores but the laptop thinks there are 8cores. An their performance are great for gamers. What do you think? And can cou explain me that, with the 4/8 cores?
I found it here:
Core i7 processors

The processor has 4 physical cores, but each core has Hyperthreading enabled. Hyperthreading allows each core to handle more than one thread, so in some instances it will be comparable to having 8 individual cores.....

One of the main differences between the i5 and i7 processors is Hyperthreading...the i5 does not support it.