In this paper, we present techniques for exploiting intermittently available resources in grid infrastructures to support QoS-based multimedia applications on mobile devices. Specifically, we integrate power aware admission control, grid resource discovery, dynamic load-balancing and energy adaptation techniques to enable power deficient devices such as PDAs to run distributed multimedia applications. Our integrated solution adapts to dynamic changes in device energy consumption and unpredictable grid resource availabilities without compromising application Quality of Service (QoS). Our simulation results indicate that our power-aware gridbased approaches, not only improve QoS of mobile multimedia services, but also efficiently load-balance the grid resources.