Evalutating tone of sound input

Hi,

I have a question about analyzing sound input in real time. I am essentially designing a program that will allow a person to play Frets on Fire (a Guitar Hero Clone) with a real electric guitar with sound wired into the sound card input. The program needs to evaluate the tone of sound input in real time and simulate a button press based on that tone. I am running into problems getting the frequency of incoming sound. I have been looking at Waveform and DirectSound, but most of what I'm finding deals with reading sound from wav file storage, and also I can't find anything to actually analyze the frequency. Just about all the references I can get my hands on have to do with simply recording and playing back sound. I'm not a particularly experienced coder, so forgive me if this is a really fundamental concept, but how would you recommend going about analyzing sound input like this?

Thanks very much.

Fast Fourier Transforms will get you from a signal to a spectrum analysis, from which you can figure out which note is being played.

Okay, I can see how a Fast Fourier Transform could get me from a time value to a frequency value. That makes sense. But how can I retrieve some time value from sound input in the first place?