I would like to quickly check that my 3D fbx files display and work correctly within a XNA environment.

Is there a XNA tool that allows me to do this?

No but its about 3 lines of code to make it yourself...

See http://msdn2.microsoft.com/en-us/library/bb203933.aspx

aless:

Hi,

 The easiest way to view a FBX file, is using the FBX QuickTime Viewer.

 You only need the free version of QuickTime and download the FBX QuickTime Viewer from Autodesk (both files are free).

You can download them here:
     FBX QuickTime Viewer, from Autodesk
     QuickTime, from Apple

 This viewer it's really good, you can even see the FBX animated models.

 -- aless

Don't have the link to hand, but in the samples section there is a winform application that allows you to load objects from the menu.