Okay, let's say you've got 35 gigs of legally downloaded music from Furthurnet and you want to change it from Shorten (*.shn) format to mp3. What do you do?

(Answer is going to be given with a Windows bias.)

Executive summary:
1.) Create a directory called C:\ShortenIsFun on your hard drive.
2.) Download shortn32.exe to C:\ShortenIsFun
3.) Place a test Shorten file in C:\ShortenIsFun
4.) Open an MS-DOS prompt window.
5.) In this window type:
       cd C:\ShortenIsFun (press enter)
6.) In this window type:
       shorten -x test.shn testOut.wav (press enter)
5.) Open your new .wav file in iTunes
6.) Set your iTunes Importing preferences to mp3 at 192 kps
7.) Highlight your .wavs in your library.
8.) Choose Advanced-Convert Selection to mp3 from iTunes' menus.

Done and done. Now set up a .bat file or a VB app or something to do all 35 gigs.

Convoluted ramblings
To begin, DO NOT search for shn2mp3 no matter how many sites beg you to do so.
    Let's pretend you want to play with shn2mp3 anyhow. shn2mp3 is a perl script that requires about five hundred other helper apps to run. To begin, you'll likely need to install Cygwin, a package of code that'll help your MS-DOS command line environment run as if it were living in *NIX-land. Cygwin is, if you have a high bandwith connection, pretty easy to install now, honestly. Download their setup app and let it run. You'll need to select the perl package, I think under utilities iirc, to run the perl script.

    Good luck. You'll have to pull down shntool and shorten and goodness knows what else. If you figure it out, please let me know.

Okay, let's pretend you're still with me. Instead of doing what you're supposed to, go to this address and grab the now ages-old shortn32.exe. You'll note there's another version here compiled for Cygwin. If you got Cygwin before messing around with and giving up on shn2mp3 and are relatively familiar with *NIX, you can grab that one and do the same thing.

Put your test .shn file, renamed test.shn, in a folder with shortn32.exe and run this command line:
shorten -x test.shn testOut.wav
Voila. You've got a .wav file. You've got two ways that I can figure to make an mp3 from this baby. Either figure out lame -- which you'll either need to compile from source (ha!) or grab binaries from some seedy location (like http://mitiok.cjb.net/), as the official lame site won't provide them to you. It's another bit of command line fun. I'm not bothering to tell you because I'm going to open all my freakin' *.wav files in iTunes, set my Importing preferences to mp3 at 192 kps, and choose Advanced-Convert Selection to mp3 from iTunes' menus.

Voila. Done. Argh. Headache.