Command & Conquer 3: Tiberium Wars will be coming to the Xbox 360. EA’s Vice President of Creative Development Louis Castle said in an interview with Gaming Steve that an Xbox 360 version of Command & Conquer 3: Tiberium Wars is currently being developed. His exact words were "They're definitely gonna release it for the 360, you heard it here."
Currently there isn't a single Real Time Strategy (RTS) game available for the 360 even though that will change with Lord of the Rings: Battle for Middle Earth II. LoTR: BfMEII "boasts a new and intuitive console-specific control scheme that will allow novice players to enjoy the game's signature strategy gameplay while giving expert players the flexibility needed to engage in a deeply complex strategy experience. Players will directly control hundreds of units in an attempt to defeat enemy armies, conquer new lands, and seal the fate of Middle-earth."
The same team that developed the Battle for Middle Earth console-specific control scheme is developing the Command & Conquer 3 game for the Xbox 360. Command & Conquer was previously available for the N64, PS1, and Sega Saturn and wasn't that great of a game because it did not allow the fast micro-management that is used for RTS games.