Do you want to know how it's done? Learn how to use Photoshop the easy way!
Find a picture of Barack and open it in Photoshop. Duplicate the layer by choosing Layer/Duplicate Layer. The filter I will be using for this is the Liquify filter. Select Filter/Liquify which will bring up the Liquify Filter Window. You will want to make sure the warp tool is selected by clicking on the little finger in the upper left hand corner. I also have the reconstruction mode set to Smooth.
The first thing I am thinking is to bring the forehead and eye brows up a bit. Choose a larger brush size for this. The size of the brush you use will depend upon the resolution of your image. I am using a brush size of 194. You want to get the area you are trying to warp right in the middle of the brush. I am going for right between the eye brows.
Now pull up a little and you get this:
Next I am going to do something with the nose. I am going to change my brush size to 55, and that is what I will use for the rest of this caricature tutorial. The arrows below show the direction I pulled on each part of the nose.
Now pull up from the top of each ear and then a little from the bottom.
Bring the chin down a bit, and bring up the corners of his mouth.
I think as one final touch, come in from the inside of each eybrow towards each other. Almost to create a unibrow.
Here is a before and after.