Well you can plug the woofer directly into the wall, but all you'll get out of it is 60hz. How much power is applied then is determined by your breaker and the woofer resistance at 60hz.
V = I * R so if your resistance is 4ohm at 60hz you'd have 30 amp applied with 120V circuit.
P = I^2 * R so 30^2 * 4 = 3600W.
I wouldn't suggest doing this for too long with most woofers. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
Now if you're looking to do a home theater subwoofer there are quite a few options out there for plate amps. The Parts express one is an ok example. The Bash amps are also ok. The KGND52100 madisound sells is probably the best option that is readily available
I've wired something similar up for one of my friends. You can use a PC power supply to power the amp. Make sure the one that you are using has enough amperage to properly power the amplifier. Hook one of the +12V rails to the amp power connector with a bridge over to the remote turn on and one of the ground cables to the ground connector. To activate the power supply cross the green cable with one of the black cables (ground), but NOT the one hooked up to the amp. UNPLUG THE POWER SUPPLY BEFORE MAKING THE CONNECTIONS and I would not recommend this for any amplifier that is pushing more than 400 - 500 watts.