It is problematical whether California will be able to put into effect the legislaion which was signed by Arnie allowing certain hybrids, including th prius, to use commuter lanes. It hinges on permission for the Feds to allow it happen. The commonly held opinion is that it will happen.
As far as being able to use the commuter lanes to cross the bridges without having to pay a toll, nobody knows. You can be sure there will be a huge objection from the operators of the bridges, e.g. Caltrans and the Golden Gate Bridge and Transportation District.
Politicians do not like to have any source of revenue taken away from them and the loss of tolls to Hybrids will not sit will with them.