procedure depends on how deep the tar has penetrated the top layer. If its through the top layer and into the paint layer, compounds like F1 etc will do nothing. If its not that deep, you can use stronger compounds like the guys above me have suggested.
If the tar is very deep, you will have to do some painting. you will have to remove paint using sand paper in places where there is tar, then respray paint, then spray clear coat. Or maybe just spray more paint on top of it and then clear coat...but that wont feel like brand new...