I would like to say that I have used this same method for recording live to 2 track straight off the mixing console. What Mike suggest here really does work well as an easy method of getting a quality recording from the main mix. Even though this article is for church sound, the methods will work with any basic, live sound, recording setup.
Mike mentions using a CD recorder to make the recording but, you could also use other types of two track recorders for the job. Personally, I made a live, 2-track recording using one of the Tascam DR05 handheld, digital recorders and the results were really good. You could also do a throwback to earlier recorders like a DAT recorder, or even a cassette deck. The method will work with any kind of two track recorder.
Here is a link to view the full article:
http://www.prosoundweb.com/article/church_sound_files_recording_live_music_to_two_track_recorders/
