Paul Helm has offered three insightful critiques (with a fourth on the way) of N.T. Wright's view of the doctrine of justification expressed in his latest book titled appropriately Justification. The book is, at least in part an effort to refute his critics, not least of whom is John Piper. Professor Helm's posts are worth reading not simply because they deal effectively with Wright but because in doing so he ably defends the biblical and historic Protestant understanding of justification by grace alone, through faith alone, in Christ alone.
Read the posts Here, Here, and Here.
Michael Horton weighs in helpfully Here, Here, and Here.
Kevin DeYoung evaluates Bishop Wright's understanding of the phrase "the righteousness of God." Check it our Here.