Frank Turk is debating a Lutheran Pastor on whether one's view of the extent of the atonement changes the Gospel.
Phil Johnson gave a message on the nature of the Atonement at The Shepherd's Conference a bouple of years back. Here is the link to the audio, and here is the outline.
I also appreciated Rebecca Stark's post from a few years ago. I liked her analogy to some people's "transactional approach" to the atonement. Her post also provides a few links to other blogs which have dealt with the issue.
The question that I'd like the answer to from anyone who rejects a view that the atonement is limited is this: if all the sin in the world is atoned for, then on what basis does God condemn sinners?