To do your cvs 'stuff' from within emacs, there is really only one key combination you need to remember:

CTRL+X, V, V

This will popup a buffer for you to type your change comment into, and prompt you to press CTRL+C, CTRL+C when finished.

This makes it almost as easy to commit as it is to save, so you can get into the habit 'Commit early, commit often' :-)