I'm sure there's a much easier way to do this, but what I would do is find an episode on YouTube that features the Turtles using the Turtlecom. Then I would go to youtube-mp3.org to convert the video into a very decent mp3. After that, I'd take the mp3 into Quicktime and edit it down to just the Turtlecom sound effect and output it as a new mp3 or a WAV. Like I said, it would probably be easier to get the sound off the DVD using video/audio editing software, but that's out of my wheelhouse. Good luck!