In medical education, pedagogical agents are widely used by computer learning systems to simulate tutors and/or mimic tutoring interactions, as well as offering just-in-time and adaptive feedback. Although the theoretical aspect of the pedagogical agents has been well-documented in literature, relatively fewer efforts have been made on how a pedagogical agent should be implemented in a real multimedia computerized simulation learning environment. In this paper, we propose a general purpose pedagogical agent architecture and implement it in the multimedia medical simulation Web-based learning system called health information network teaching system (HINTS) to further facilitate students' learning and thereby make the HINTS a more helpful educational tool. Our focus is the design of the general purpose pedagogical architecture and its implementation in a multimedia computerized simulation learning environment. A preliminary students' performance evaluation result is also reported. We analyzed how to evaluate the students' performance and how the hints were given by the pedagogical agent. The system has been installed in the National Cheng Kung University Medical Center, Tainan, Taiwan for trial purposes. Some experiments have been conducted and the results have shown that the pedagogical agent indeed help the students in their learning process.