Light Burst Effect

Start a new document (640x480)

Press "D" to reset your color palette to black and white.

Go to Filter->Render->Clouds

Now go to Filter->Pixelate->Mosaics. Set Cell Size to 20 squares

Now apply Filter->Sharpen->Sharpen. Now press CTRL+F about 5 times to reapply

Now go to Filter->Blur->Motion Blur

Angle: 90°,
Distance: 999

Now go to Filter->Distort->Polar Coordinates. Select Rectangular to Polar

Next, go to Filter->Render->Lens Flare.

Brightness: 100%,
Lens Type: 105mm Prime

Position the lens in the center of the image

Now apply: Filter->Distort->Ocean Ripple.

Ripple Size: 15,
Ripple Magnitude: 5

Use the round marquee tool and make a selection around the white glow. Then go to Select->Feather: 20px

Then go to Filter->Distort->Spherize: 100% , Do it 1 more time but this time 50%

Now you can deselect.

Now apply some radial blur: Filter->Blur->Radial Blur

Amount: 30,
Method: Zoom,
Quality: Best

Now just play with the colors, either using color balance (CTRL+B), or Hue & Saturation (CTRL+U)

Click to enlarge