Don't waste your money at Best Buy...
Get this (it has all the wiring you need, fuse, connectors, etc):
8 Gauge Amplifier Installation Kit
Jaydogg pretty much covered the basics of installation...just a note...on the ground. They usually say the shorter the ground the better...I think many recommend a maximum of a 12" ground wire. As mentioned, you need your ground to be touching BARE METAL on the frame. If the surface is painted where you're attaching your ground, take a file/sandpaper/wire wheel and hit it til it's bare and gives you good metal to metal contact. A bad ground will leave you with nothing but trouble.