I know there is a thread vaguely on this already, but its surely important enough to have it's own dedicated thread for all information / news on the upcoming DLC/expansion for XCOM: Enemy Unknown.
What we know so far:
- Due to be announced on Tuesday 20th August 2013
- 30 new achievements have appeared on Steam
- Reported to be called XCOM: Enemy Within
- Definitely an expansion to XCOM rather than standalone