The low cost of the video-camera and its user friendly features has increased the number of the video amateurs. It is not easy to obtain good results and it is important to critically judge your videos in order to improve your skill.
Digital videocameras help you in shooting very good images.
It is better to use a videocamera with 3ccd: the underwater use conditions are extreme and this technology allows you to obtain incredible good results (otherwise not obtainable with a single ccd videocamera).

You can buy an original waterproof case or try adapt another one. The latter will be surely cheaper, but also bigger, as it has not been created for the specific videocamera size.
Minimum requirement is the external command for start/stop, manual/automatic focus regulation and zoom.
A further feature is the white balancing (not always available) and the shutter speed.
For further details, it is better to consult a technical manual.