I would second the suggestion of GoudX above.
Rehearsing the Serve: http://www.youtube.com/watch?v=cUeCEfUwyq4
It is a lot faster to learn a nice serve motion without having to learn how to time the toss at the same time.
Once you feel you have a nice rhythmic swing, time your toss to the serve motion (rather than have a hitch trying to time your serve motion to how high you are tossing the ball).
Coach McCraw has some tips for a nice swing:
McCraw Serve Fundamentals http://www.youtube.com/watch?v=WuIgTyh4aDs