Over the last decade the telecommunications domain has gone through historical changes. The evolution of networks, technologies and telecommunications vision has experienced rapid changes. Mobility becomes a must and there is an increasing demand by mobile end-users for services. Delivering value added services anywhere can be possible by taking advantage of the flexibility of mobile ad hoc networks (MANETs). Traditional service architectures fail to address the characteristics of such new networks. This book proposes a novel architecture to provide services in the challenging MANETs. Two types of MANETs are addressed: the stand alone and the Multihop Cellular networks (MCNs). Architectures and benefits from the network operators'' point of view are presented and discussed. Since SIP is widely used in today''s 3G networks, SIP servlets are considered as the basis framework. The work represents a first step in the area. Therefore, the book may help professional, student or researchers interested in service architectures and Mobile Ad hoc networks as an introduction to the domain but also to go further for commercial solutions or address open issues.