Colin Litster writes some of the coolest Blender tutorials that I know. His most recent work is a very detailed introduction to creating a realistically animated ocean.
Over the last few years I have been experimenting with techniques to help convey realistic large scale oceans and seas. In my previous tutorial I discussed techniques that would enable a stormy ocean to be created to the horizon with reasonable results. However, the techniques suffered from the effects of repeating patterns and restrictions in panning or moving the camera. One important aspect that was missing was wave crests. This was pointed out to me by several more nautical colleagues than I. Realising that I would need several seas for my production, from calm weather through to force 12 hurricanes, I have been developing techniques to make that possible within Blender.
You'll find the first part of his tutorial on his website, www.cogfilms.com.
Update: Colin just emailed me to tell me that the tutorial is now complete. It has become a 4(!) part tutorial. Enjoy!