Mobile computing is associated with mobility of hardware, data and software in computer applications. With growing mobile users, dynamicity in catering of mobile services becomes and important issue. Polices define the overall behavior of the system. Policy based approaches are very dynamic in nature because the events are triggered dynamically through policies, thereby suiting mobile applications. Much of the existing architectures fail to address important issues such as dynamicity in providing service, Service Level provisioning, policy based QoS and security aspects in mobile systems. In this chapter we propose policy based architectures and test results catering to different needs of mobile computing.