Mythic Entertainment[Wikipedia] is a subdivision of EA Games, itself a subdivision of Electronic Arts. EA Mythic is currently developing Warhammer Online: Age of Reckoning, and they are also the creators of the reasonably successful Dark Age of Camelot[Wikipedia].
After being acquired by EA, Mythic Entertainment was renamed EA Mythic, but the name was later changed back to Mythic Entertainment.
On June 24, 2009, Mythic Entertainment fused with BioWare and is called now BioWare Mythic.
See Warhammer Online Development Team for more details on the staff working on the game.