PaintStop

From ZBrush Info

PaintStop is a sketching and painting plugin for ZBrush. The PaintStop brushes are designed to feel as natural as possible, and the interface to be simple and intuitive, speeding your workflow and unlocking your creativity.

With PaintStop you can quickly sketch concepts for a new sculpt, work on illustrations for print or web, or simply have fun painting.

Download the PaintStop plugin from the Download Center

For plugin installation instructions see here.