Development of mobile packet networks GPRS and UMTS created additional ways of delivering new services and contents to mobile users. Since the network access cost must be decreased, mobile network operators have to find new ways of content charging. In the first part of this thesis a short overview of the currently used charging system is given. This system supports only access charging and content charging for the content over the SMS bearer. In the second part of this document, three models that enable content and service charging, not supported in currently used systems, are described. A model that supports content, service and access charging is explained firstly. This model is based on using the AAA system, mobile IP, the QoS broker system and the balance management system. An overview of these systems and their integration into the whole model is described. This model, besides charging, also supports a traffic monitoring and gives provision for access to specific contents and services. Second model described in this thesis is an M-commerce model, which supports trading of physical and non-physical (i.e. digital contents) items. An overview of basic building blocks and a description of two basic M-commerce models, the account-based model and the token-based model, is given. Finally, an experimental model for WAP URL based content charging is described. This section gives a description of basic components and the model functionality. It also provides an example of practical implementation in recent charging models. Models presented in the thesis can be used as a pattern for content charging solution in the mobile packet networks.