actually, in AMD land, HTT stands for HyperTransport Technology as well.
your actual HTT bus speed of that cpu is 1000mhz, doubled to 2000mhz. data is sent on the upswing and downswing of the clock, so it is "double pumped" to an effective frequency of 2000mhz. it doesnt really have anything to do with the number of cores.
cpuz would show four if you had a quad-core (amd, i dont know about intel,but im sure its the same) cpu.
alvin is correct that it is normal for you to see 2 cores, since your cpu is a dual core.