A recent Twitter post from the official Mass Effect 2 feed indicates the game will have free DLC when the game releases later in the month. The post states "BioWare will not be charging extra for any new Mass Effect 2 content on launch day." The post also mentions that further details will be provided next week, which gives us hope that the content isn't contingent on drinking soda.
Mass Effect 2 launches on January 26. Be sure to check out our Mass Effect 2 primer here.