The analysis of network traffic and customer usage patterns is critical for the network operation, capacity planning and targeted marketing of the cellular industry. This data analysis task presents both an opportunity and a challenge for data warehousing technology because of the huge amount of wireless calling data and the dynamic nature of the usage reports. We have developed a data-warehousing system to address the issues of both the performance and the flexibility of the usage analysis reports. Our system collects traffic data from a wireless network and provides the following functionalities: basic reporting, dynamic modeling, customer profiling and usage forecasting. This paper focuses on the usage analysis reporting for the traffic by an individual customer or a group of customers on a subset of a network or the network as a whole. Based on the traffic usage, it describes three different usage forecasting models for capacity planning. A combined application of data warehousing and statistical analysis to a customer calling plan selection is also presented.