Once upon a time I wrote about how to convert iTunes music into more compatible formats. Well, this is an update.
At some point Apple changed their iTunes interface and so that old post, AAC to MP3 (M4A to MP3), is kind of out of date. Here are instructions to help you convert AAC or M4A iTunes music into MP3 files (or WAV or RIFF is you like).
In iTunes, click Edit > Preferences. You'll see this screen here:

Click the Import Settings button to get to here:

Click the Import Using drop down menu and choose a new encoder, like the MP3 encoder shown above.
If you want to have custom settings, choose Custom... in the Setting drop down menu. That will bring you to this screen to set yoru MP3 options:

Set your MP3 options however you like. I've set them there for maximum quality. Hard drive space is cheap, so why sacrifice audio quality? There's no reason to.
Click OK there, and you'll see the Details changed as shown below:

And that's about it to get the settings right. Now, you only have to right-click in the iTunes playlist to get the "Create MP3 version" option as shown here:

Click that and you've got your music in MP3, which is more compatible with more software and more hardware players.
I hope that helps some people out.
Cheers,
Ryan