If they are M4A's downloaded from iTunes, no legal software does it, only a couple of underground apps. If your M4A's are not protected, there are more options. I use foobar2000 as my audio player/converter, but that's just my preference.
tunebite is legal it uses the "analog loophole" tunebite.com but it costs money I just burn the protected aac files to a regular audio cd on cd-rw and rerip the tracks then erase the disk. both of these ways are legal
You are right about tunebite. It's legal, but cost money. You forgot to mention that in theory it also diminishes quality. As for freeware, burning and ripping back to mp3 is your only legal choice.
The .m4a files extension means the Mp4 audio file isn't copy protected! I don't know why you would want to convert mp4 to mp3, or lossy to lossy for that matter since there will be some quality loss. But if you need to do it I recommend dBpowerAMP (v10). Download it here... http://www.dbpoweramp.com/bin/dMC-r10.exe Don't forget to downoad the Mp4 (AAC) decoder/encoder here... http://www.dbpoweramp.com/codec-central.htm Ced
Converting the files is more out of curiosity on my part. I tend to want to learn how to convert the many types of audio/video files just so I know how to do it. Thanks for the links.