This paper discusses the utilization of distributed energy resources on the distribution side of the power grid to provide a number of ancillary services. While the individual capability of these resources to provide grid support might be very small, their presence in large numbers in many distribution networks implies that, under proper control, they can collectively become an asset for providing ancillary services. An example is the power electronics interface of a photovoltaic array mounted in a residential building roof. While its primary function is to control active power flow, when properly controlled, it can also be used to provide reactive power. This paper develops and analyzes distributed control strategies to enable the utilization of these distributed resources for provision of grid support services. We provide a careful analysis of the applicability capabilities and limitations of each of these strategies. Several simulation examples are provided to illustrate the proposed approaches.