Photoshop animation experiment 2-Cut-out animation (Terry Gilliam-Monty Python style) - How to...

 To begin with, you need the right picture. If you're doing a celebraty, then try to get a picture where they are facing the camera (or almost facing the camera) and have their mouth closed. As an example, I found this rather unflattering picture of Katy Perry on Google so that I could show you the technique using her, because I like Katy Perry.
 << Here's the picture.

Right, so we 'Copy' the picture and open photoshop, click 'File' then 'New' and the settings should automatically size the background to be the right size as the layer. If this isn't so, you might be better saving the image in your documents then clicking 'File', 'Open' and selecting your image that way.

Be sure it's also a 'Film & Video', and change the timeline by clicking the button shown so it looks like this:

Then change the frame rate to 0.1 by clicking this:

Now we can get started. To begin with, we need to cut out the part that will be moving, so select the "Polygonal Lasso" tool found here:

You can use this tool to select your characters mouth. Make sure to include their chin too.

Then 'Cut' and 'Paste'. This'll put the chin onto a separate layer, and make it easier to move. Use the fill tool and flood fill the background layer, black. This'll make the inside of your character's mouth darker. 

(On a separate layer)

Creat a new frame so you can begin to move your character's chin. Then move the chin down slightly, opening the gap in the mouth a little bit - make another new frame, then open the mouth wider. Repeat until their mouth's are open enough, then begin to close their mouths again. You can repeat this for the length of audio you are using.

That's it! You should be complete, just save the file as an appropriate file type for you, and you are finished!