Does it exist?
Since on their WEB PAGE the author wrote the following:
But my frustration with Visual Basic (which is what I wrote the GUI in) has finally reached critical mass. Visual Basic does not like Unicode. Well, it doesn't like displaying Unicode.
So I've decided to start over from scratch. The really cool part is that I'm using wxWidgets, which means I can write the code once and compile the GUI for Windows, Linux, and Mac. (Mac users, keep in mind that a MacMP3Gain already exists)