This document is designed as a comprehensive resource and guide for computer-using educators who wish to expand the scope and magnitude of their computer power through telecommunications. The major focus is on the microcomputer's ability to communicate with other microcomputers via telephone lines. Emphasis is placed upon information services and databases that are easily and economically feasible for both the professional educator and student to reach. Following an introduction, an in-depth discussion on the basic electronics underlying computer telecommunications is provided. Subsequent chapters are devoted to the educational uses of: (1) the CompuServe Information Service; (2) The Source; (3) Delphi; (4) Knowledge Index; (5) the Bibliographic Retrieval Service (BRS), focusing on BRS After/Dark; and (6) computerized bulletin board systems. Telephone numbers, addresses, and costs are included as they existed at the time of writing. Also included are many actual "screen dumps" (the actual contents of the monitor screen while online). In addition to describing the specific services available, topics of broad educational impact such as electronic mail and teleconferencing are discussed. (JN)