The XNA Model Viewer
This program allows you to load an FBX file and view it in XNA. It provides a way to test a model. It also exposes all of the bones associated with the model so you can determine appropriate rotation and translation axis.
The XNA Model Viewer project is now hosted on Codeplex at http://modelviewer.codeplex.com/
You can install the program using ClickOnce from the Codeplex site and updates will be automatically installed as they become available.