One of the easiset things to do is turn a photograph into an impressive pencil sketch in just a few steps in photoshop. All that is needed is any photo. The steps will work with any photo.
This is a free stock photo from http://www.deviantart.com/
Step 1 : Open the photo in Photoshop.
Step 2: Press CTRL+J to duplicate the Background layer;
Step 3 : Press CTRL+SHIFT+U to desaturate the layer.
Step 4 : Duplicate Layer1 which was desaturated.
Step 5 With Layer 1 copy highligted press CTRL+I. The image will look like a negative.
Step 6 : Change the Blend mode of Layer 1 copy to Color Dodge.
Step 7 :The picture turns white. There may be a few black dots or it can be completely white.
Step 8 : Go to Filter>Blur>Gaussian Blur.
How far you drag the Radius depends on the effect you want.
I am happy with this effect.
Other photoshop tutorials are here