3Dgeek: There are two fairly straightforward techniques you could try get some glow in your ghosts:
1) Create a local light and parent it to the ghost object, ensuring it is at the centre (ie remove the default Y+200 offset). Make the light very local (start: 5, end: 500 - depending on your object size). Then make your ghost object material two sided. Set the front to 0.0 visibility, and the back to a high specular value (1) and somewhat visible (0.4), with a low rough value (around 4). The light will cause bright specular highlighting across the far surfaces of the ghost object, and the edges will be less lit, creating the effect of a glowing centre. This has the great advantage of your ghosts actually casting a glow on any objects they fly near.
2) Create a single flat plane (a 1x1x1 cube and delete four points). Create an image of a gradient white circle on a black background (sample attached), use this as a transmap on a new texture with a strong glow (in whatever colour you require, white or blueish-white). Add this as a child of your ghost, and adjust it to be slightly larger than the ghost object. You may need to push this slightly behind your ghost object to avoid unsightly overlaps between semi-transparent objects. If you set this new object to be facing the camera, it will keep itself aligned in the scene and work even if you move the ghosts around.
Here's a very crude preview using both techniques: