Hi Smokindog,
Beacuse of mp3 licensing restrictions, you have to download the LAME encoder (the site info shows when you try to rip an mp3 in Audacity.)
For collaboration, you should use the OGG option instead. OGG format files sound better when compressed for emailing, and, more, importantly, they don't lop off part of the beginning data during repeated encoding/de-encoding, so you stay in perfect sync when you import/export your collaboration files. As long as all collaborators have Audacity, everyone is good to go.
Take your Wav files, import them into Audacity, convert them to Oggs and save them on your PC.
Write an email, attach the Ogg file to the collaborator, and when they receive it, they load the oggs into their Audacity, re-convert them into Wavs and import them into their DAW or PC audio program.
This works very well. When you arrive at the final tracks you all like, you can then mail the final Wav files to whoever is doing the mixing.
Best,
CC
