The usage of interactive applications increases in handheld systems. In this paper, we describe a system-level dynamic power management scheme that considers interaction between the CPU and the WNIC, and interactive applications to reduce the energy consumption of handheld systems. Previous research efforts considered the CPU and the WNIC separately to reduce energy consumption. The proposed scheme reduces the energy consumption of handheld systems by using the information gathered from the WNIC to control the CPU voltage and frequency when interactive applications are executed. Experimental results show that on average the proposed scheme reduces energy consumption by 46% when compared to DVFS (Dynamic Voltage and Frequency Scaling) for the CPU and DPM (Dynamic Power Management) for the WNIC.