For those of you looking for tank tops with built-in bras, these actaully are pretty good. I'm a DD and the underwire ones actually support.
http://www.solutions.com/jump.jsp?itemType=CATEGORY&itemID=167&path=1%2C2%2C4%2C14%2C167
http://www.solutions.com/jump.jsp?itemType=CATEGORY&itemID=167&path=1%2C2%2C4%2C14%2C167