Here you go. A lens flair that you can use for animations.
Download: http://www.mediafire.com/file/nd3jj9om2g16132/Lens+Flair+Rig.zip
How to use:
Import the rig into your animation.
Parent the rig to a camera.
Use the position, rotation, scale, and alpha sliders to adjust it according to where the light source is in your shot.
If done right, effects may be similar to those in the GIF above.