*May be a slight exaggeration.
I tried putting regular cream sunscreen on Little Miss' part (she won't go for a hat) and it was a pain. It was almost impossible to get the whole part covered and it took several bath times to get the white mark off of her scalp. Spraying on a little sunscreen is definitely a much better way to go.
My second update is a bit of a downer. In my research for the original sunscreen post I had seen a brief mention that some countries' drug regulating bodies were concerned about the potential for inadvertently inhaling spray-on sunscreen while applying it. It was such a small reference I figured it was not big deal. There hasn't been any professional research into this concern yet but I was lucky enough to do some amateur research.
I was wrong. The first time I sprayed sunscreen on Little Miss I thought my lungs were on fire. From then on I was super careful to make sure we were outside and Little Miss was facing away from the main stream. I would suggest the same for anyone else wanting to use spray-on sunscreen. (And consider yourself fairly warned--your lungs may be permanently damaged.)
Now get out there and have some fun in the sun!