I recently found out that when using the 3D rotation and transformation tools in Flash CS4, the movieclip or object that has the transformation applied to becomes slightly blurred. I have found that if you apply a 200% scale transformation to the movieclip you want to have the rotation effect applied to, and then nest it in another movieclip that has 50% scale transformation, it results in the end product being much crisper.
Click here to view and example of what I mean. The panel on the left is the standard output after applying a 3D transformation. Notice how the text is blurry. The movieclip on the right, while still not perfect, is noticeably crisper. The middle movieclip is how it would look without any 3D transformation.
Click here to download the source .fla.
Note - you will have to download the Tweener tweening classes for the file to compile.