From Agree Software:
Agree Free M4A AAC to MP3 WAV AMR OGG Converter is excellent audio converter which can help you convert M4A and AAC files to popular audio formats. Agree Free M4A AAC to MP3 WAV AMR OGG Converter can convert M4A to MP3, AAC, AC3, AMR, OGG, and WAV, and also convert AAC to MP3, AC3, AMR, M4A, OGG and WAV with friendly interface and lots of useful features. The conversion is performed in batch mode, which means that you can easily convert an entire list of audio files to one audio format you want with very little effort. Version 5 may include unspecified updates, enhancements, or bug fixes.