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
Downloading and Installing Audacity and the Lame MP3 encoder
How to Install LAME MP3 Encoder in Audacity - YouTube
Lame MP3 Encoder for Mac - Download Lame for Audacity | MacUpdate