Today the FIA ruled the Brawn GP, Toyota and Williams cars as being legal. Ferrari, Red Bull and Renault said that the rear diffuser is not allowed according to the new rules but Formula 1's governing body ruled in favour of Brawn, Williams and Toyota.
This was the most likely outcome as the FIA hadn't said anything about the diffuser during the Australian and Malaysian Grand Prix. But Ferrari still think that they are right and they are waiting to see why the FIA ruled against them.
I think that Ferrari should give it up and just get on with improving their car instead of worrying about other teams. They should accept the fact that just because the Brawn diffuser is different and better than their it is illegal.