software used to draw knots

• Peter Suber's list of knot software — REALLY good list
• KnotPlot — focused on mathematical knots, but still generates pretty awesome-looking renderings
• Mathematica package "KnotTheory" — focused on mathematical knots, however, it has a well-developed notation format
• KnotsBag — Celtic knots

notation systems for knots

• non-mathematical knots
  • ....?
• mathematical knots
  • Alexander-Briggs notation
  • Dowker notation
  • Conway notation