Here are 10 brushes made from actual pencil scratches. These are large brushes (all are near 2000 pixels), suited to both high-res images as well as web-ready graphics.
This set is useful for creating various sketch effects (such as the sample image). These brushes render a very realistic and “loose” sketch effect. You may also want to use them as grunge brushes for your “dirty” work.
Photoshop CS and higher