Audacity guide - audio editing free software, convert WAV to MP3, WAV to OGG, MP2 to MP3, MP2 to WAV, MP2 to OGG, MPA to MP3, MPA to WAV, MPA to OGG,
Audacity tutorial: Converting to mp3 or AAC and other formats, example: Matthew Smith - epic orchestral synth music for film and game effects; Buanzo's LAME mp3 library
How to Export an Audacity File As an MP3 in 2 Simple Ways
MP3 Export Options - Audacity Manual
How to Get Higher Audio Quality when Using Audacity
Suggested Audacity Settings for MP3 Export | Missionary Geek