The following keywords are used to help with the Pixel Joint search tool and to help search engines with appropriate key phrases. Make sure to take some time and add keywords to your pixel art submissions. It actually helps!
Doom 2-D avatars, Doom 2-D icons, Doom 2-D pixel art, Doom 2-D forum avatars, Doom 2-D AOL Buddy Icons
Huh, we with friends have made remake of this fanmade version. Now it supports OpenGL and a lot of gorgeous new capabilities.
http://doom2d.org (Russian language, but you can find and download an english version easily)
P.S. Also it have a powerful editor, and tons of additional maps and models.