The Galaxy Note includes a stylus which Samsung calls the "S Pen". It can simply replace the use of a finger in situations where precision is needed, but it is also equipped with a "shift" button, which when pressed enables other functions such as grabbing screenshots (which can then be drawn on using the stylus) or for writing sticky notes with drawing/handwriting, text input, and pictures. (Source)
Questions related to this specific stylus should have this tag. For other brands/models or generic stylus, please use the stylus tag.