Mobile telephone communications and the Internet are converging and may eventually operate on a common technical platform, using TCP/IP networks as the main backbone medium. Mobile telephones are converging to Internet terminals, allowing the user access to email, Web browsing and all the other Internet services currently available from a desktop computer environment. In order to provide improved infrastructure for Global System for Mobile (GSM) based Internet services using 2nd and 3rd generation (2G and 3G) the mobile network providers have the requirement to generate revenue for the services they provide. To do this the mobile network providers first need to capture the charging and billing data from the network. This paper describes the evolution of the GSM telephone networks and future mobile Internet services, via the General Purpose Radio Service (GPRS) and Universal Mobile Telecommunication System (UMTS). The methods for collecting the charging and billing information and charging models for processing this data into subscriber bills are discussed. A selection of proposed Internet charging models are applied to the mobile network market and their relative suitability is examined.