It seems we might get some additional details about some new downloadable content for the original Mass Effect soon. Mentioned in a BioWare Twitter update, no solid details have yet been made available, but it was said that something more might be revealed later this week. Here's the update's exact wording:
"Getting the feeling some news about the next ME1 DLC may be coming this week. Keep your eyes peeled."
Since Mass Effect was released back in November of 2007 only one bit of DLC, called Bring Down the Sky has been made available. The original game received high praise upon its release, and a sequel is expected early next year.