[Jackson]

You want your sig to do this?

It's possible using Photoshop, go to Window at the top, then click on Animation.
That will open up a new window for you, from there it's pretty simple. Organise your layers palette so that each layer is your sig(just copy and paste 'em in). Hide them all, except layer 1, then click the button for Next animation, then hide all except layer 2... etc.

After that's done, just set the slide time between each slide and save as .gif