In June 2011, the release of TDM 1.06 added support for Mac OSX.
While this was not an easy achievement given the number of build components that were required (launcher, updater, game dll, etc), it was much easier than the project to bring all the build requirements for the Doom 3 GPL code into the project. This task is now (finally) nearing completion.We are asking the OSX community to sign-up at the forums and help with TDM 1.08 install and play-testing. There is also a graphical installing in the works and we hope to have that available shortly as well.
Graphical installer (currently only 1.07)