AudioFinder uses the LAME Encoder for encoding MP3 files. AudioFinder does not ship with the LAME Encoder binary so you will have to download it and install it from one of the sites below. Once installed AudioFinder will find it and use it for all your MP3 encoding needs.
AudioFinder will look in the following locations for the lame executable:
/usr/local/bin/
/usr/bin/
and the AudioFinder Application folder.
The LAME Project official website
Download from MacUpdate
Download from Version Tracker
You can also find binary versions of LAME at Rarewares