Higher Dimensional

Hyperspace Structures: Exploring the Fourth Dimension - Explains the properties of the hypercube and hypertorus. Shows models and video clips. Includes information on how these images were created using software and mathematics.
info.lboro.ac.uk/departments/ma/gallery/hyper/

Mark Newbold's Java Stuff - Java applets that show intersections, morphing, and stereoscopic renderings of four-dimensional polytopes and optical illusions.
dogfeathers.com/java/

Regular 4d Polytope Foldouts - Java applets to view the shapes by rotating them.
www.weimholt.com/andrew/polytope.shtml

Uniform Polychora - Some images, and the naming scheme that the author has used to categorize over 8000 of these shapes with.
members.aol.com/hedrondude/polychora.html

Uniform Polytopes in Four Dimensions - Tabulates the convex uniform (Platonic and Archimedean) polychora.
members.aol.com/Polycell/uniform.html