According to the work of J. Scott Carter you can draw pictures of knotted surfaces in four-space in several different ways. I know the man is a real artist in this, but did anybody come across some software that does this for you ? See for example: http://www.jscottcarter.com/)
I guess you can figure out a parametric equation for a knotted sphere, and pay a trip to Mathematica-land, but I haven't done this.
This is probably a more specialized version of Topology software)