You won't believe this until you try it.

Take a paper towel, fold into an 1/8 of its original size. Now it's nice and thick. Soak it in cold water, the colder the better. Lay it over the sap and lightly press it onto the body (not too much as you want the water to stay in the towel). The towel with stay on the car by itself, even on a vertical surface. Leave it there for a couple on minutes. Then use the towel to wipe the sap off.

I've not heard that tip before, but I have heard of using an ice cube pressed against pine sap to release it from automotive paint.

I got this information from another forum. I should have given it quotes.