A Microsoft spokesperson told GeekWire that they oppose the SOPA bill as it is currently drafted. So far, Microsoft hasn't shown any blackouts, like Google, WIkipedia, and thousands of other websites have. No word yet on if they plan to do any blackouts.
"We oppose the passage of the SOPA bill as currently drafted. We think the White House statement points in a constructive way to problems with the current legislation, the need to fix them, and the opportunity for people on all sides to talk together about a better path forward." – Microsoft Spokesperson to GeekWire