The built-in function "write[]" can save a Decker sound clip as a .WAV file.
If you have a sound named "sosumi" (like in the default guided tour deck) you could export it by typing the following in the Listener:
write[deck.sounds.sosumi]
If you want to export lots of sounds, it wouldn't be that hard to make a tool to automate the process.
If you're trying to export sounds because you want to use them in a different deck, you can skip the export process and use the Font/DA Mover to import sounds or other bits and pieces directly into a new deck.
Does any of that help?