Blender normal mapping help

I read an old blender tutorial that said i will need to invert the red and green channels after generating normal maps to be use in commerial game engines. Is this the case with Blender 2.5? would it be better to generate my normal maps in xNormal?

this answers your question loud and clear

http://wiki.blender.org/index.php/Dev:Shading/Tangent_Space_Normal_Maps