The script is in the post - it's a 2-line script. You'll need to install MP3::Splitter first (Open Terminal, type "cpan MP3::Splitter"). Just copy and paste the post into a file on your computer and name it "makesample". Then run it using the instructions in the script's comments.
Yes, I did assume you're on a Mac. Command will still work if you're on UNIX. I don't do Windows, but someone else can possibly help you get Perl running if you are on that OS.