Perhaps we could change how digital content (e-books, MP3s etc) is offered for sale. Instead of "buy a copy of this item", offer it as "pay for the effort that went into creating this item".
Buying a copy means buying some bits, and since bits sound insubstantial and making copies of bits is effortless, it doesn't sound like it should be worth much money.
But when you frame it as paying the content creator for their effort, that sounds (to me) like something that's worth more.
This is about changing how people view what it means to purchase digital content. There's obviously a big question about how that could be achieved and I'm not sure of the answer.
One component of that is the user-interface in online-stores. I wonder if you could replace the 'buy' button with something else? Replace it with something that suggests you are giving money to pay for the effort that went into creating that content.
Perhaps it could be a 'pay' button, with hover-text saying "pay for the effort that went into creating this item".
Obviously you'd want it to be something pretty short and sweet.
update: I wonder if the visual "branding" used by Creative Commons might serve as a model for this. There are a range of buttons that represent particular Creative Commons licences (see the image to the right of this paragraph for an example). Perhaps you could have something analogous to this and by, instead of a 'buy' button, having a special button that represents this notion of paying for the creation of the content instead of for the content itself.