How to animate hand written letters?

I am trying to create a simple animation. I have an image of a hand written word and i would like to animate it so the letters appear in an order that looks like the word is being written. Please explain in simple terms what you think would be the easiest way to do this. I am fairly new to Flash Professional and I would like to figure it out. I plan to upload this to YouTube. The animation only needs to be like 4 seconds long. Thanks!