We know from the producer's podcast that when Ben mentioned to Locke about the "box" that it was a metaphor. This box can turn your dreams and thoughts into reality.
Next week's episode is "The man behind the curtain", which I am assuming is referring to Jacob. I'll leave who I think Jacob is to another thread

. The title of the episode has an obvious link to The Wizard of Oz (as did Ben's first name - Henry Gale). The wizard of Oz made people's dreams and wishes come true. He wasn't "magical" but had the resources to give the 4 characters in the story kind of what they wanted.
We know that the Others are resourceful; they (used to)come and go via submarine, they had a "live" video feed of Juliet's sister, they bought Locke's father to the island. Therefore I believe that Jacob is the conduit between the people on the island and making their thoughts a reality. The fact that he knows their thoughts and dreams is in itself "magical". But making their dreams come true is fairly easy with his endless resources.