This paper reports the results of a doctoral research pilot study that paired a researcher with an experienced classroom teacher for a 12-week time span with the goal of effectively integrating the use of Geometer's Sketchpad (GSP) into the classroom teacher's practice. Using a teacher development experiment, the researcher created an apprenticeship model to foster the transmission of the knowledge to the classroom teacher required to successfully teach with Geometer's Sketchpad. Specific results indicate a positive change in the facilitation of mathematical communication and inquiry-based instruction in the classroom teacher's practice as well as sustained use of GSP beyond the time span of the pilot study. General results include the development of the constructs of technological knowledge (TK), technological pedagogical knowledge (TPK) and technological pedagogical content knowledge (TPCK).