I recently gave a talk on REST vs. WS-* at both QCon San Francisco and ApacheCon US. The slides can be found on WSO2 Oxygen Tank. I suggest reading the ApacheCon slides as those are slightly updated from the other one.
At ApacheCon Roy Fielding spoke right before me on REST. It was great to listen to Roy present his vision and to hear about REST from the horse's mouth so-to-speak. It was an honor to have him introduce me and then to have him right there to provide additional anecdotes and corrections to my points :).
Comments welcome, especially from those who feel I got it wrong (on either side).