Although language learning in 3D Virtual Worlds (VWs) has become a focus of recent research, little is known about the knowledge and skills teachers need to acquire to provide effective task-based instruction in 3D VWs and the type of teacher training that best prepares instructors for such an endeavor. This study employs a situated learning approach to teacher training and explores what online teaching skills emerge in the process of collaborative situated learning, how these skills develop, and whether collaborative situated learning is an effective method of training instructors to teach in 3D VWs. Six English as a second language (ESL) teacher trainees enrolled in the Teaching English as a Second/Foreign Language (TES/FL) program participated in the study. During the preteaching stage, teacher trainees developed language tasks to implement during the teaching stage with eight EFL students in 3D VWs. Blackboard wikis used for designing tasks allowed for observing the acquisition of five 3D-specific, integrated skills. The analysis of teaching sessions recorded through screen capturing software Camtasia Relay in conjunction with the teacher trainees' wikis and journals demonstrates that for this group of teachers, a situated learning approach was an effective method of teacher training.