Froggy, the rotor system can be seen as a wing in a rotating reference frame and the fixed wing in a linear reference frame. The fixed wing may be easier to visualise, and is also discussed more on the web, but the basics of flight apply equally to rotorcraft...
Puntosaurus, in answer to your question i would say that the change of lift vector is just as valid for rotorcraft as it is siezed wings. In both cases the cause is the downwash across the wing/rotor, which results from the unbounded tip vortex.