I don't remember if I said something about this before, but if not, check out Format Factory here:
I use this all the time...it can convert one kind of music file to another (m4a to mp3, etc.), convert a video to mp3, create an ISO (disk image) from a CD-ROM, convert one video format to another, one photo format to another, and more. Best of all, it's free.
This has been incredibly useful for me; maybe you'll think it's handy also.