Quote - This one I just let run over night.  I'm restarting it since I accidently picked the wrong normal map for the boots.  It does, however, demonstrate the power of normal maps.

What I do to create a normal map is, I take either the diffuse texture or the bump map into GIMP.  If it is the diffuse, I then run the Normal Map plugin (not included, but available online from here).  I usually choose Prewitt 3x3, as it doesn't make it over powering.  Prewitt 5x5 makes it pop more, but it can look pretty fugly, too.  The normal map tutorials I've seen also mention using the green channel when using the original texture.

If it's the bump map, I first invert the colors (colors->invert), then I run the normal map plugin with the same settings as before.

I usually use crazybump and work with the diffuse map. The bump map doesn't work as good and I can't sharp texture with it.  I learned after a lot of trial and error how to adjust the settings to get the type of texture I want .

Crazybump is a great program to use and it easy too.

There is a video tutorial on ytube on crazybump. It shows how to use the settings for normal maps