well...
Cool Edit is a .wav editor for pc, running under Windows.
It's very stable and fast-working with a lot of possibilities.
From my point of view it's the best audio-program around.
Some people won't like this, but I'll tell you how to get the registered version for free.
Surf to
http://www.syntrillium.com and download the demo-version of Cool Edit 2000.
Then, go to
http://www.astalavista.com and download the crack-program to change your demo-version to a fully-working one.
With that Winamp-plugin called Pacemaker you can slow down without changing pitch, while you're listening to the song. You can set the sliders and almost on the same time you change the tempo.
With Cool Edit, you can set how much slower you want to have your song, and it changes the whole speed (without changing pitch), but not directly when listening to it.
I hope this is a bit clear, my English is not so good.
Greetings,
Maarten.