While there was nothing revealed about Doom IV during John Carmack's QuakeCon 2010 keynote, the master programmer for id Software did reveal something that will make some mod authors happy. Carmack announced that the game source code for the first person shooter Return to Castle Wolfenstein and the later stand alone free game Wolfenstein: Enemy Territory are both available to download now from id's FTP site.

As with previous source code releases from id, these fall under the GPL agreement which basically states the author is able to use the code for both free and commercial games as long as he or she does not claim the code is their own creation. Return to Castle Wolfenstein, developed by id and the now defunct Gray Matter Studios, was released in 2001. Wolfenstein: Enemy Territory, developed by Splash Damage, was released in 2003. You can get both the PC, Mac and Linux versions of Wolfenstein: Enemy Territory right here at Big Download.

Download the Wolfenstein: Enemy Territory GPL Source Code at Big Download (6 MB)
Download the Return to Castle Wolfenstein GPL Source Code at Big Download

[Via VG247.com]