BioWare has said PC owners of Mass Effect will get Bring Down the Sky content for free when the game is released on 6th June.
You will need to register your game and join the BioWare online community to do so.
Bring Down the Sky was the rather disappointing content pack released on Xbox Live in early March.
It had you putting a stop to a Batarian terrorist plot to crash an asteroid station into a nearby and helpless colony.
Despite 90 minutes of fresh content, Bring Down the Sky was largely just another combat-heavy side-quest using the same side mission building layout seen numerous times in the main quest. Only at the end did it brighten up.
Still, it cost GBP 3.40 back then. Now it is free. We'd take it for nothing.
You should know all this by now, but the desktop version is a "conversion" and not a "port" according to BioWare, and is optimised to feature things like hotkeys for less interrupted action and individual squad commands for better tactics.
The loading problems, texture pop-ups and lengthy elevator rides of the Xbox 360 version should be erased here, too.