The Plugin Site

If you want a realistic pencil sketch effect, you have to do it with a graphic tablet by hand. Available filters only produce a more or less realistic effect depending on the image.

To get some links to pencil effects, please go to
http://thepluginsite.com/search/graphicsgalaxy.htm
and enter the keyword pencil

Photoshop's own Skecth -> Photocopy does a decent job. Play with the controls, and then afterward - Go to Edit>>Fade.....here you play with both the controls and the layer blend modes for different effects. Edit>>Fade>>Luminosity works well.

After that use the burn and dodge tools to add shadows and highlights.

have you tried Buzz Pro 2?