just figured this out today...

http://www.filefront.com/9637416/DDS-Plugin-for-Photoshop/

No idea if anyone else knows about this..

however this pluggin is for photoshop and it creates .dds files..
but also it has a filter to create tangent space normal maps..
not the grey scale ones... but the purpley blue ones..

install the pluggin then

create your unit textures and texture your uv mapped unit..
open the .dds texture in photoshop then click filters, nvidia tool, normalmapfilter

choose the appropriate settings to create the tangent space normal map.

hope someone finds this usefull

If that's the nVidia plugin, it is indeed very useful. But not for making TSnormal maps for FA. Because FA doesn't use that standard "pearly blue" kind. It uses a reduced set of data utilizing color for one direction and alpha for the other instead of 3 color channels for 3 different directions.
But thanks for the link. It isn't all that obvious or easy to get Photoshop to export DDS files.