Solar Sail???????

[apache]

Actually, sailboats do not sail with the wind pushing the sail. They operate by the wind passing over the sail, like air passing over a wing. In otherwords, sails are nothing more than airfoils. Water resistance really has nothing to do with it. In fact, a sailboat makes the best speed when the wind is blowing perpendicular to the direction of travel. The only direction a sailboat can't travel is directly into the wind.
Anyways, I may be wrong about the actual arc of motion allowed by a passive sail, but the way it would move in other directions is by orienting the sail in an angle to the path of the solar wind. The wind particles hit, and bounce off of the sail, and so by Newton's 3rd law, generate an equal and opposite force. The way the sail is oriented determines the direction the desired reaction force will be in. And so you can move the ship in directions not along the path of the solar wind.