GPRS (general packet radio service) is a new nonvoice service that is being added to existing IS-136 TDMA (time division multiple access) networks in the United States and GSM (Global System for Mobile Communications) networks in the United States and Europe. It provides for the transmission of IP packets over existing cellular networks, bringing the Internet to the mobile phone. Anything the Internet offers, from Web browsing to chat and e-mail, will be available from GSM and TDMA service providers via GPRS-enabled devices. Nikhil M. Deshpande and Jay Gilbert explain how GPRS works and explore how well it works.