I created an object, and I wanted it to glow. I used to just place points of light around it, and parent them to it, but using the emit option in the materials seemed so much easier. But when I gave it an a higher emit than 0, it went only a small distance before the light stopped. I turned it up to 200, and the object was white with light, but the light didn't go any farther. Oh and I changed the color, and nothing happened.
To get this kind of interaction in Blender render you'll have to enable Indirect lighting with the Approximate Gather method.
From the Blender Reference Manual's page:
Indirect Lighting only works with Approximate gather method.
The emission color of the emitting object's surface comes from the diffuse color multiplied by the emission strenght (Emit).