Surround Sound

I just built my first computer with help from the awesome people at this forum. I have a question about HD and surround sound audio now. Here's my current build:

core i7 920 @ 2.66 GHz
6 GB OCZ DDR3 1600 MHz (at 1066 MHz)
Western Digital Black 640 GB hard drive
Intel DX58SO Motherboard
HD Radeon 4870x2
Pioneer DVD drive

My question is this: from the specs of the motherboard

Channels: 7.1 Channels
Audio Chipset: High Definition Audio (HDA)

Does this mean that I should be able to buy some 5.1 or 7.1 channel speakers and a blu-ray drive and expect to get the best of HD audio? I saw some HD Audio pins on the motherboard: do I need to buy some other peripheral to connect to those in order to get HD sound? Basically, what can I do to turn this into the receiver of a surround sound system???

I looked it up and yes you do. Although you will need an amplifier to power all the speakers.

Oh. Cool. So the setup would be a line out from the back of the pc to the subwoofer, speaker wires from the sub to all of the speakers....and how does the amplifier fit in?