The reason people do this is to achieve a faster FSB, and gain more performance for the same speed. Since the HTT/FSB is linked to the RAM, you'll increse the RAM's speed too, which will eventually require you to loosen the timings. Check your motherboard manual, but you'll want to look for 'Frequency and Voltage' from the main menu. If not that, you may want to see if there's a Core Cell listing. Again, consult your manual.
When overclocking, your two best friends are [google]Memtest[/google] and [google]Prime95[/google]. Memtest is run off a floppy or CD (just open the .ISO file with something like Nero and burn it), so set BIOS to boot off the floppy or CD and let it run for several hours to give the RAM a good beating. If you start coming up with errors, then you'll need to loosen the timings, reduce the speed, or increase the RAM voltage a little.
After you've found a stable speed, then you'll want to use Prime95 in Windows. Let it run for at 24 hours straight. If you don't get any errors, then the CPU should be fine at that speed. If not, then you either need to increase the voltage a little or look at better cooling. There's also the CPU's limit as to how fast it can go, period.
You'll need to go slowly, like 5MHz increments at a time, test, tweak, and test again. This isn't something you'll simply crank up the speed on and go on your merry way. You are running things out of spec and out of warranty.
Hypertransport is a low-latency interconnect standard, developed by the HyperTransport consortium, which AMD is part of. AMD has used it to replace the FSB on the Athlon64, in part because of the speed and lower latency.
