A new "success" for string theory has been released by the Princeton group. You can read about it here and here. You can also see why some feel it is not such a big deal here.
Essentially what has happened is the people at Princeton have shown that string theory is consistent with gauge theory, specifically N=4 supersymmetric Yang-Mills theory. This is a very important check since N=4 supersymmetric Yang-Mills theory describes low-energy particle physics.
