Realistic wave

hi, im struggling to make a nice looking wave without much success, i have tried using frame by frame and also by actionscript, neither i could find any good tuts even here on how to ahiceve this kind of effect without using 3rd party programs such as after effects and the like
basically is just the sea as background and a big wave coming towards the screen and splashing against it, its very simple but im just not getting it >_<

if anyone knows any good tut or pointing direction will be apreciated