Use the Neighborhood Selection tool, and give it the same searching neighborhood parameters you used in the IDW model, and use the point feature class you used in IDW for the input points. For the x and y coordinates, use the center of the raster cell. This will make a layer of the points that were used as neighbors for that cell.
If you're just wanting to do IDW with inverse distance squared as the weight, this is what IDW does by default.