Camry :: 2006 - Whining Noise From Under The Hood

We have a 2006 camry with he 4 cylinders at about 106,000 miles. All of a sudden, the car has started a loud whining or purring noise. I have checked all my fluids and the appear to be at proper operating levels and there is no leaking anywhere that I can see. I replaced the water pump last year but have not replaced a belt on the car. The noise starts when you crank the car up and sounds like it is in tune with the engine. The steering doesn't appear to be affected although if there has been a gradual change the ease of steering I may not notice, but it is not at the point of being a manual steering without power. I cannot hear it through the speaker (like a bad diode). No real performance change in the engine or transmission except when decreasing speed the downshift of the transmission is more noticeable, like the gnome is dragging the through the gears.