Step 1: Create a black circle using the shape tool (hold SHIFT and drag to make a circle). If you don't see a circle tool, click "U" and you should see a menu at the top of your screen that has a number of shapes. Pick from that.
Once you've made the circle, right-click its layer in your Layers panel and click "Rasterize".
Step 2: CTRL-CLICK the circle layer to make a selection around it, then go to SELECT > MODIFY > EXPAND, and expand it 20 pixels. You should have something that looks like this:
Step 3: Go to FILTER > NOISE > ADD NOISE and crank that sucker - add as much noise as you can.
Step 4: Now, with the expanded selection still active, go to FILTER > BLUR > RADIAL BLUR. Select the "Zoom" blur method, best quality, and a strength of 60. Click OK, then hit CTRL-F if you want to make your ball fuzzier.
Step 5: If you want a multi-colored ball, skip this step. Otherwise, hit CTRL + SHIFT + U to desaturate the ball layer (remove all color). Double-click the layer and click "Color Overlay" in the layer style/effects menu. Set the blend mode to "Overlay" and pick a color!
And the final, colored fuzzy ball:
Here's a variation that shows one of the uses of this tutorial - a dandelion! All I did was select white as the color overlay, blend the layer a bit more with the radial blur, and played with the patterns settings in the layer style menu to get the "speckled" effect.
