I can't find the original blog posting that inspired me to make my fruit and veggie wash, but it's one part white vinegar to three parts water. I like using vinegar to wash my fruits and vegetables since it's a standard food product and won't hurt you if you don't wash it off. I've got a big spray bottle I keep under the kitchen sink devoted for my fruit & vegetable wash. I labeled the container in permanent marker and also indicated the amount of vinegar and water for the proper ratio for refilling. 
I spray all of my fruits and veggies that don't come pre-washed (i.e. not the bagged salad), rub it around a bit with my hands if possible, and then rinse with water. I even spray items like avocado and melon where you don't eat the skin because you're going to cut through that skin to get the insides. So if you cut through the dirty outside, the knife is going to transfer that dirt inside to the part you're going to eat. I don't know if spraying off my fruits and veggies has really helped me avoid spreading the germs that might be on my produce, but I figure it's an easy step that could possibly help prevent us from getting sick, so I might as well continue.