Normalizing is not the best way to "master" your final tracks, in my opinion. The reason being that you could very well end up with a bunch of tracks that are different from each other volume-wise, at least in listener perception.
In the normalization process, the software looks for the highest peak and pushes the entire track up in volume until that peak is just below digital "0". But here's the problem: Let's say you have one track where the peak is much higher than the rest of the song, and another track where the peak is not much higher than the rest of the song. What will happen is that the relative volumes of the tracks will be off. So the peaks will be the same, but the rest of the tracks will be far off from each other.
The usual way to avoid this is to use a limiter on your final mixes. The limiter raises up the whole track, and allows you to control what the peak will be. Anything above this peak will be lopped off, allowing the rest of the tracks to remain at the desired volume.
Also, there's no rule that says that all the tracks on your album have to be at *exactly* the same volume. A little ebb and flow can be a good thing.
I know you are looking for free, but if you are on a Mac, there is an inexpensive program that will do everything you need in one piece of software. It's called DSP-Quattro and does high quality normalizing with a greaet deal of control, plus you can create a playlist of your tracks and burn your CD's right from the program itself, no Toast or Jam needed.
