When I share my garageband file into iTunes, it automatically converts to a "mp4a" extension file. It seems to be the only option. How would I convert to an mp3 file instead, since not everyone has the ability to read mp4 files?
It should be an AIF file. Are you selecting, "Send Song to iTunes"? That's the way to get AIF. Then convert to MP3 in iTunes.
I have to assume that you are using the "Export Song to Disk" which I am 80% sure makes an AAC file. You need to go with the afore-mentioned "Send Song to iTunes".
Thanks again! I found out my problem also had to do with not setting my preferences to mp3 for importing, that's why it would not show as an option to convert.