Log in to the bioware social network. From there, select profile from the menu, and in the profile submenu, my registered game promotions. The download link is on that page for each item you're purchased/redeemed.
That dosen't work for me, i have registered my copy of ME2 but it dosent show up on my profile site, the game it seems to register is DA. The only way i can get the downloads is by booting up the game and loging in to cerebus and just clicking on the download new content on the main menu. Some of it is good, Zaeed, Overlord. The most of it i would say is not that good as its mostly new skin textures one or two new weapons, which cost a bit.
I also have a question about Mass Effect 2, At the moment there is a problem with the broadband line, British Telecom have said that the lines need replaced but there not going to do it anytime soon, so my connection is on average speed 11.0 mbps (was 54), signal strength very low, which means my connection also keeps dropping so its nearly impossible to connect to the Cerberus network, and i am in the middle of a game with most of the DLC. Is there away to use the stuff which i have paid for, without the network as i have no idea if or when bt is going to fix the line or am i screwed?