One way to do it is to record your track and duplicate it to another channel on your recorder. Then shift the pitch of the duplicated track up a third or whatever and "hey presto" instant harmonies. You can then mix in the degree of processed vs non processed using the faders and pan for extra air !
My instructors page and www.studiotrax.net for all things recording.
my toons Brought to you by Dr BadGAS
my toons Brought to you by Dr BadGAS