Stella: Polyhedron Navigator - A program for creating, visualising, and printing nets for polyhedra. - http://home.aanet.com.au/robertw/Stella.html
Polyhedra by Bob - Images and software. Poly is a free DOS program that can be used to study the truncations and transformations of the Platonic Solids. - http://members.ozemail.com.au/~llan/polhed.html
Polyhedra 2001 - OpenGL program which displays the uniform polyhedra and related shapes in real time. The shapes may be morphed in to their duals, exploded, truncated and unfolded into a net. Free download. - http://gratrix.net/polyhedra/2001/
POLY - Shareware Macintosh/Windows software for exploring and constructing polyhedra. Flattened versions (nets) of polyhedra may be printed and then cut out, folded, and taped, to produce three-dimensional models. - http://www.peda.com/poly/
PPL: The Parma Polyhedra Library - A C++ library for the manipulation of convex polyhedra. Distributed under the terms of the GNU General Public License. - http://www.cs.unipr.it/ppl/
PEEK - A program to interactively explore arbitrary dimension polytopes through the use of cross-sections and projections. - http://www.cs.utah.edu/~gk/peek/peek.html