I'm uncircumcised, and though I've of course heard it develops, I've never seen it myself. Last year, the water went off and I couldn't bathe for two weeks. I still never saw any. Women develop smegma too (much more of it, naturally), but most are quite surprised when you tell them, simply because most people wash far too much for it ever to make an appearance.
The circumcision posse have put quite a lot of pictures on the web. Do a search and they'll turn up. Bear in mind that the pictures they post are real horrorshows, and most men have never seen their cocks look that disgusting.