More details here(thanks for Pob for pointing this out):
http://www.youtube.com/watch?v=Ri0vrJ-y2zM
The DLC is actually important for the storyline of the game it seems. However,you either need to pay more for the DLC at LAUNCH or buy a much more expensive version of the game.
The version which has it is the N7 Collector’s Edition which is around £55 AFAIK. The DLC costs 800 Bioware points on its own which is around £6 to £7.
Comment by chap in video on the development picture doing the rounds saying why there is a launch DLC:
http://social.bioware.com/forum/Mass...9439691-1.html