Mike, I just came across this tutorial where he uses both one and two flashes to take a self portrait. Good info here, I thought. Though I haven't tried it out on myself yet, his results were great! (I hope it's OK to post this link. If not, moderators, please remove it. Thanks.)
https://www.youtube.com/watch?v=qH59MX5WlRU
https://www.youtube.com/watch?v=qH59MX5WlRU