With the latest PSN Update in Europe, the Dead Money DLC is now available in the US and Europe (and thus worldwide? I don't really know how this works) on the PlayStayion Network.
The DLC is also available on D2D, for North and South America. Note it's a Steamworks game, so you'll have to play it on Steam if you buy it on D2D anyway.
The DLC is also available on D2D, for North and South America. Note it's a Steamworks game, so you'll have to play it on Steam if you buy it on D2D anyway.