How does a dual-core processor works?and also processors with hyper-threading technonology?

Question

In dual-core processors like pentium d, does it use additional wirings to do multitasking or bluetooth?

In hyper-threading technology, how does the screen displays all demanding applications concurrently when they are being used?

Answer 1

Dual Core:
http://www.short-media.com/review.php?r=261

Hyperthreading:
http://www.viewcast.com/products/Niagara/hyperthreading.html