The purpose of this study is to determine the appropriate network system for using the Digital Textbook in a u-Learning environment. South Korea has invested a substantial amount of capital in the Digital Textbook project. However, its network system is not sufficient to support the u-Learning network system. To ensure the success of the Digital Textbook project, it is necessary to establish an optimal network environment in which to facilitate the development of content and manage the rapid changes in information and communication technology. To determine an appropriate network system, a comparative analysis has been conducted regarding a network environment for the Digital Textbook based on the actual case of South Korea. As a result of this study, Wireless LAN (WLAN) appears to be the most appropriate network system for the Digital Textbook project among WLAN, Mobile WiMAX, and High Speed Downlink Packet Access (HSDPA) network systems. Subsequently, this paper presents useful policy guidelines for the Digital Textbook project in South Korea as well as for other countries interested in the u-Learning project.