POLY http://www.peda.com/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.
Polyhedra 2001 http://gratrix.net/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.