Another option to using a rinse aid for dishwashers is using an acidic product like Lemi-Shine. This goes in the detergent drawer (it says to fill the whole main wash compartment, but I used to get good results using half Lemi-Shine and half detergent). It is basically citric acid and it keeps deposits from forming on your dishes. A lot of people feel that it's more natural than a dishwasher rinse aid.
The thing with Lemi-Shine is that it will also clean your dishwasher, which is good but you have to be careful with it at first. You have to run the dishwasher through an empty cycle with nothing but Lemi-Shine in it; otherwise, the gunk that it stirs up might wind up on your dishes!