Melissa Jill - Hi Mike,
Great question! I always expose in camera for the subject, so occasionally a portion of the background is blown out. But it's never an important part. Here's a post that gives insight into how I pick backlighting situations. It's all about the shaded background.
http://www.melissajill.com/blog.cfm?postID=791&my-favorite-lighting-backlighting
Mike - Nice work Melissa! On the backlit photos, how do you retain detail in the faces without blowing out the background;is that post processing? Thanks