i thought that you use a variable transparent sprite in front of the view. then you render the camera to the bitmap of the sprite while it is invisible. then you blur the picture (or transform it elsehow - described below) and turn it back to it's previous transparent value. by adjusting alpha and the blur radius, you can control strength of the effect.
with a shader (or by the 'bright'-flag) you can either set addive, subtractive or multiply to the sprite and maybe invert it, too. by combining those effects you get great effects.

examples:

• addive + blur => glow
  
• subtractive + invert + blur => negative glow, dreamy, dark effect
  
• addive || subtractive + invert + glow => control over contrast and brighteness
  
• subtractive + glow => ugly effect (looks like a bad painting ;-)
  ...
  

hope you now understood what i meant.

JOEY.