Saruman for or against Sauron?

[Kath]

I think it's sad how the film shows Saruman as being, like you say, a puppet and little more.

I agree. He was actually very cunning and powerful in his own right. He used Wormtongue to infiltrate Rohan and was doing a fine job of corrupting them until Gandalf showed up. And the power of his voice is never really shown in the film either which is shame as I always thought this a very interesting power in the books.

Saruman wasn't really working for Sauron though I don't think. I would say that they were working in tandem toward a common goal. Both wanted the Ring and power over ME and had Saruman got the Ring he would have had a fair shot at this as the Ring would have magnified his powers.