Understanding FFT libraries help

Hello,

I've found so many threads on the FFT for arduino but quite frankly, I'm kind of confused. There is a lot of information and I'm not familiar with audio and signals and sampling and all that jazz. I've downloaded many FFT libraries, but when I open them up, I'm just completely confused on how they work. From what I've gathered, they:

  1. Take a certain amount of samples and store them in an array (128 or 256)
  2. do some jazz
  3. are 8 bit or something

I just want to use the information, process it and then shift it out to make a simple FFT spectrum analyzer.
How would I accomplish the FFT side?

I liked this FFT explanation - An Interactive Guide To The Fourier Transform – BetterExplained -

Ah yes, I've read that before but quite frankly, I don't have time to sit down and make an FFT library.
Is there one out there that is just like, here it is, here is how you use it. Whether it is made for the arduino library or not.

You might find something useful in my thread here: http://arduino.cc/forum/index.php/topic,96562.0.html

Pete