^ Just for what it's worth, Any 4-ohm stable amp will also be 8-ohm stable but will do (at best, in most cases, especially on a budget) half the power.
It doesn't work the other way around, though. And get a job, punk, I've been collecting a paycheck since I was 14.
This isn't entirely accurate, but will give you a basic idea;
if an amplifier does
1000 watts into a 1 ohm load, it'll do
500 watts into a 2 ohm load
250 watts into a 4 ohm load
125 watts into an 8 ohm load
So your two 4 ohm speakers can be wired into a 2 ohm load, an 8 ohm load, or two 4 ohm loads, depending on if the amp is a mono-channel or multi-channel amp.
Also realize that the power the amp puts out is relative to the gain setting, the volume knob, bass boost, etc.
This isn't true of all amplifiers, there's always an exception, but it should help clear up some misconceptions about wattage and ohms you may have.
Welcome to the addiction, if you really did read that website (which is huge, you didn't read it all.) you'll be doing this for a loong time. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif