According to a teaser by Bioware on its official Twitter page, It will be making a major announcement tomorrow. The Tweet which says “2morrow will be a great day for BioWare fans. Just sayin.” sounds more than internet-speak and can be a clue to something big.
The use of "2morrow" sounds like an announcement for something big, Like a game title. Well it could be Mass Effect 3 "WOW" but if they already had something as big as Mass Effect 3, it would had been revealed at E3 2010. It can also be an announcement for Dragon Age Origins 2 or even DLC content for current titles.
Well i say we should wait till "2morrow" and wait. We will update you as soon as some big news comes up.