I think Algae will provide an excellent biodiesel source. Research is continuing in this area. We can't expect change overnight - small cars are now just starting to see an uptick in sales and SUV sales are dropping.
My only concern is with the water required to grow the Algae. I haven't seen anything that addresses this yet.
http://www.treehugger.com/files/2008...s_solazyme.php http://blog.wired.com/cars/2008/01/driving-around.html http://www.solazyme.com/