You can read a copy of the opinion here.
According to the U.S. Supreme Court, a two-member Board is powerless to exercise any authority. At the time of the three recess appointments, the Board only had two members.Therefore, by ruling that Obama's three recess appointments are unconstitutional, today's appellate-court ruling effectively moots every decision from the Board subsequent to the recess appointments, most of which went against employers.
Expect this to be appealed to the Supreme Court.
UPDATE: The U.S. Chamber of Commerce has much more on today's ruling here.
2ND UPDATE: Here is a statement from NLRB Chairman Pearce on today's ruling.