I would like to know how to add a glow effect to nparticles. Tanx in advance.

Pandora,
Is this to for the light streak that you posted about last week?
Hopefully that is coming along well.
There are two types of glow in the example you posted before.
Shader Glow wich can be adjusted/added on each material with the “Glow Intensity”
(most materials have it under the Special Effects tab. It is found at the bottom of the Common Material Attributes on the Particle Cloud Shader.)
Check out my previous post for some more details on adjusting the glow look.
This type of glow “looks” like it is glowing but it does not cast light in the scene.

The other type of glow in the example is created by rendering the scene with Mental Ray and enabling Final Gather.
To make the particles cast light assign a material that has some incandesence.

The default settings for Final Gather will not give you enough light so you can either crank up the
Primary Diffuse Scale in the Final Gather Render Settings(try 500 to start and adjust from there.)
AND/OR
Incandesence on the Material of the Particle (raising this above 1 will totally blow out your shader...but maybe you will like the look)

You will also need to increase the Accuracy, Point Denstity and Point Interpolation in the Final Gathering Settings to get really high quality even light from the particles.
(because the default settings will give you some crazy sprakley noise.)

Hopefully, these two things will give you a lot of control over the final “Glow” look of your particles.
All the best with it.
~Ben