Hi, byard. There is a great product for this available to consumers. It is called kerosene. If you have an approved container, you can buy it at some gasoline stations. You can also buy it in the camping section of some mass merchandisers. You will also want some rags, rubber gloves and 2 cheap scrub brushes.
Assuming that your pool is outside, this is fairly safe to use. Do not use it near a source of ignition and certainly do not smoke while using it. Just slosh some on the spots, give it 10 minutes, slosh some more on and rub and scrub the tar spots away.
Then wash the area down with Tri-Sodium Phosphate (TSP), which you can get in paint stores and paint departments of mass merchandisers. Sprinkle the TSP on the area, leave it sit for 10 minutes, scrub the area with the second brush. Don't kneel down to do this or the skin your knees will tell you that this was not a good idea later. Finally, rinse with a garden hose and keep the rinse water out of the pool.
Wear your gloves when working with the TSP and the kerosene. Leave the rags and the brush that you used for the kerosene outside for a couple of days to dry completely and then discard them. Don't use this method if you have an indoor pool.