If you are looking for the "ripples in spacetime" sense of the term (which is by far the more commonly used sense) you should go to the Gravitational waves page.
The term "gravity waves" is in very common use to refer to the "ripples in spacetime" phenomenon, especially in light of the recent announcement from the LIGO project. But that use of the term is not actually correct. See gravitational-waves-vs-gravity-waves-know-the-difference for a good explanation of this point.
Gravity waves, on the other hand, are an ordinary mechanical phenomenon that is influenced by a planet's ordinary gravity. Most waves that one can see on bodies of water are not classified as gravity waves, because gravity does not play a specific role in the wave behavior (other than, obviously, making the water lie below the air). But some water waves are gravity waves, instead of the more common waves that are simply wind-driven. Tsunamis and tides are examples of true gravity waves. Other true gravity waves, while very rare, have been observed.