1)   Daniusoft M4A Music Converter 2.0.24
Daniusoft M4A Music Converter is a powerful yet easy-to-use converter that can convert m4a to other audio formats such as mp3, wav, ape. It has high conversion speed and supports batch mode.

 2)   M4A to MP3 Converter 1.2.3
M4A to MP3 Converter can convert M4A video or audio files to MP3 files. M4A to MP3 Converter can also convert other media files to MP3 files, these media files may include WAV, OGG, WMA, WMV, ASF, ASX, MPEG-1, MPEG-2, MPEG-4, MP4, M4A, AAC, MOV.

 3)   OJOsoft M4A to MP3 Converter 1.5.3.0218
It can convert M4A to MP3 easy and fast. In addition, it can convert M4A to MP2, MP4(audio only). Safe to install and free to try.