It really depends on what Dick LeBeau does. If he uses his usual LB blitzes all day to try and disrupt Warner, they will lose. Warner has a quick release and is one of the best (if not the best) in the league at picking up/beating the blitzes. Plus, that'll take guys off of Boldin, Breaston, and Fitz. The Steelers need to get pressure from just their front 4, and need to pressure Boldin, Breaston and Fitzgerald on the line.
I do not think that the Steelers offense will be able to do much against the Cards defense. The Cards have held the Falcons, Panthers, and the Iggles to under 100 yards rushing. All are very good rushing teams, so Willie Parker shouldn't be much of a factor. I don't see Roethlisberger doing much either.
Final Score:
Cardinals 24
Steelers 17