Do you believe in magic? You will after using The Levelator to enhance your podcast. And you'll be amazed that it's free (for non-commercial use).

So what is The Levelator? It's software that runs on Windows or OS X (universal binary) that adjusts the audio levels within your podcast or other audio file for variations from one speaker to the next, for example. It's not a compressor, normalizer or limiter although it contains all three. It's much more than those tools, and it's much simpler to use. The UI is dirt-simple: Drag-and-drop any WAV or AIFF file onto The Leveler's application window, and a few moments later you'll find a new version which just sounds better.