Spot the Signs. Do you have a good relationship with your manager? Is he or she relatively reasonable? Do you have regular one_on_ones where you talk about your career goals and growth? If so, it's likely that your boss will accept your resignation with grace, help develop a plan of action for your last two weeks, and maybe even attend your farewell happy hour.
The Hand_off. Finally, state your willingness to help out with the transition. You don't need to go into great detail (and definitely don't promise anything you can't deliver), but a couple of lines stating that you'll ensure a smooth wrap_up of your duties will show that you're in the game until the very end. Obviously, feel free to adjust this a bit based on your experience and your company culture, then submit it via the typical procedures at your company.