One of Iran's top military commanders warned Saudi Arabia on Sunday that its decision to send forces to Bahrain to quell protests by Shiite Muslims would spark unrest at home, a semiofficial Iranian news agency reported.
Stirring up trouble in Saudi Arabia (Saudi Arabia has a substantial Shia population in their eastern oil-producing regsion) would certainly provide a distraction for Iran to help Syria use maximum bloodshed to put down the spreading unrest in Syria.
UPDATE: This could be related:
Syrian security forces besieging the city of Dara have been ordered to use "any means necessary" to crush the rebellion that sparked the weeks-long uprising against the regime of President Bashar Assad, a Syrian military source said Saturday.
Perhaps just the threat of Iranian subversion in Saudi Arabia will keep the Saudis quiet as an Alawite (fringe Shia) regime slaughters Sunni Arabs in Dara.
My guess is that there will be far less world outrage over the destruction of Dara than there was over the "Jenin massacre."