I never really understood all the uproar centering on the ending of Mass Effect 3. Dead, is never really dead in a science fiction video game. I'm sure if the developers wanted to bring Shepherd and crew back for a fourth installment, they could figure out some way to make that inconvenient death go away. Still, there were lots of people that were very angry at the ending of the video game.
EA and BioWare promised a while back that a new ending that expanded on the original ending would be offered. If you play Mass Effect 3 on the Xbox 360, that expanded ending is now available for download. The download content is free and is available right now. Be prepared to wait a while, the download is 1.85 GB.
The teaser page for the new ending offers very little detail of what you're going to see. It simply says the download is an expanded ending for Mass Effect 3. The ending has additional scenes and an extended epilogue to show the impact of Shepherd's choices on the future of the galaxy.