I don't think they'll release them, but that's just a guess. They certainly won't review the items you missed or anything like that.
If you have $100-$150 (not sure of the current price), Transcender makes practice tests that are very close to the MS exams, sometimes a bit harder. They usually come with three practice exams. If you can pass all 3 then you should have no problem passing the real exam.
If you do go with Transcender, I suggest the following:
1. Take the first exam cold - don't study. See how close you are, look at the results and concentrate on any area you did bad in.
2. Retake the first exam and make sure you pass with a reasonably high score.
3. Take the second exam as in step 1 and 2.
If you do the above, by the time you take Exam 3 you'd better be passing it on the first try. If you don't, it might be a sign that you need some more real world experience (what the exams are *supposed* to measure).
The Transcender used to put references into the MS documentation as well. So for each question/answer, they give a full description of why the right answer is right and the wrong answer's wrong and references to look at. It's a GREAT way to quickly learn a lot about .NET, even if you don't want to take the exam. But you have to be willing to read a lot as you go through the tests.
-Ner