Thanks to HomeLanFed for their article reporting highlights from the Doom III keynote panel at QuakeCon
, which featured id CEO Todd Hollenshead, lead designer Tim Willits, programmer Robert Duffy and lead animator Fred Nilsson. They discussed how "making a map for Doom III is a lot more of a collaborative effort than in previous Doom games because of the level of detail"
, and mentioned that "both Linux and Mac OS X versions of Doom III are moving in close development with the PC version... they will have Mac and Linux files available for download when Doom III is released for the PC... An actual Mac retail box for Doom III is a possibility but a Linux retail release is unlikely."
They also confirm Doom III for Xbox is being converted by Vicarious Visions
and "will be basically the complete experience that PC gamers will get."