Hi guys,
I don't know the Windows side of things. If you've got an Apple, use iTunes to convert the songs. Insert a CD and import the tracks you wish, then in the Advanced Menu at the top of the screen you can convert from AIFF to MP3 at various rates and vice versa. Highlight the song title in iTunes and under the File Menu, select show song file which will show you where the file is on your Mac. You can then point to the file for uploading, etc. If your music is on MD, you'll have to do a straight audio transfer in real time, recording the song into your Mac's audio input (typically a stereo 1/8' jack),then drag the file onto iTunes before converting. I hope that helps.
Mike