Removing paint spots on your hardwood floor depends on the type of paint you used and the type of finish on your floor.
For removing latex paint start with soap and water first. I imagine you already done this, so now use denatured alcohol and a soft cloth. The denatured alcohol will dissolve latex paints while leaving polyurethane floor finishes alone.
The denatured alcohol will soften and damage acrylic floor finishes. If this is the case just use warm water and a mild soap. Plan on doing some scrubbing. Fresh latex paint should come up without damaging the floors finish.