Currently the baked normalmaps from blender cannot be used in many other applications because the normals are baked in a different direction.

I suggest a feature to change the direction of the baked normals to allow a greater scale of use.

This image is the direction used by most applications
http://www.metalliandy.com/blender/xnormal.jpg

This image is the direction used by blender
http://www.metalliandy.com/blender/blender.jpg

(the UV's are a little different on each image)

Just a simple set of buttons to switch between the two would be great :)