It's been happening for quite a while now. Here's a recent Atlantic report on a Baghdad neighborhood that has undergone such a change. The piece isolates just one street and goes house to house to chronicle the shift. Click on the link to see the map in full detail.
This article available online at:
http://www.theatlantic.com/daily-dish/archive/2007/07/ethnic-cleansing-in-iraq/226443/
