The 2008 Nissan Rogue will be using speed-sensitive Electric Power Assisted Steering (EPS), a sophisticated system that helps correct for road irregularities and improves overall steering feel.
Conventional power steering systems use an engine-driven hydraulic gear, which saps power and efficiency from the engine. The 2008 Nissan Rogue's new EPS system uses an electric motor, rather than the engine’s accessory drive. This new system helps improve fuel economy and eliminates the hydraulic noises typical of conventional hydraulic power-assisted steering systems.

For those of you with a taste for the technical side of things the following link has a great writeup and model of the typical EPS system. Automotive DesignLine | Electric power steering: one good turn deserves another