PlayStation 3 Gamers will be able to buy Mass Effect 3 digitally off of PlayStation Network on March 6, the same day the game launches in stores. Players will also be able to preorder the game off of PSN starting today. As an added bonus, players also get DLC, the M55 Argus rifle. As an added bonus, players who preordered the game off of PSN will also get a special Mass Effect 3 XMB theme for their PS3.
Source: PlayStation Blog