There are a lot of websites devoted to polyhedra. Here are some of the best.
This one is run by Jonathan Bowers: http://www.polytope.net/hedrondude/home.htm.
Here’s the portal-page to George Hart’s pages, with links to a LOT of cool stuff he’s made: http://www.georgehart.com/.
I don’t know who runs this one: http://polyhedra.org/poly/
This one is Robert Webb’s. He’s the person who wrote Stella 4d, the program I use most often on my own blog to create polyhedral images: http://www.software3d.com/Gallery.php. (Also, while we do share a first name, he is not the same person as me, as a few readers of my blog have thought in the past.)
Craig Kaplan has a page of links to other pages of his, right here: http://www.cgl.uwaterloo.ca/~csk/projects/. Of those, my favorites are the sections on John solid near-misses (http://www.cgl.uwaterloo.ca/~csk/projects/nearmisses/), as well as on symmetrohedra: http://www.cgl.uwaterloo.ca/~csk/projects/symmetrohedra/
Jim McNeill’s polyhedra site is here: http://www.orchidpalms.com/polyhedra/
Here’s a good one, but I don’t know its creator’s full name: http://colinspics.org/index.htm
Finally, one by Vladimir Bulatov: http://www.bulatov.org/polyhedra/index.html
This is definitely not a complete list. If you know of other good polyhedron-oriented websites, please leave links to them in a comment on this post.