After you have opened the image you are doing the animation to, creat a new layer, then set your Foreground Colour to white, then grab the Brush Tool, and use this brush.
When you have done that, zoom in to your image twice, and place a dot on the image with your brush, make sure you are on the second layer though. When you have done that go to Layer > Layer Style, Then click on Outer Glow, Change the Opacity settings from 75% to 100%, then click on the Contour Box:
And change it from Linear to Half Round.
Then you should have somthing like this:
Now Jump to Adobe Image Ready
Zoom In twice on your Image, then click on your second layer. then move the dot to where you want to start the Animation.
When you have done that clcik the New Frame Button in the Animation Box:
Now you should have 2 frames now. Then Move the dot across, about 5pix across, using the Arrow Keys, on your Key Board, then press the New Frame Button Again, then keep on doing this all around your Image/Text, it takes allot of time and patients....you will end up with about 30 to 200 Frames. When you have finished, go to File > Save Optimized As... Then your done....i added a fade effect at the start and end to mine....
Here's what i got, it had 161 Frame's.
Source:
Photoshop Animation Moving Dot Animation Tutorial