Canadian link. And here is the American link.
One one side of the coin, is the argument that the book will be more widely read, especially in high schools, if the "N" word is changed, On the other hand, some people feel that Twain wanted us to be uncomfortable with the racial epitaph and taking it out is contrary to Twain's intention. For a more serious look at the question, Katie Davis has interviewed Dr. Alan Gribben, the editor who made the decision to make the change. It's worth listening to.