We present the implementation of a web-based CMC (Computer-Mediated Communication) system, in which video streaming technology was incorporated, to support peer assessment in a teaching practicum course. The findings revealed that the pre-service teachers showed positive attitudes toward using the system. They considered it an effective tool for sharing with and learning from peers. They became more engaged in the peer assessment process. They appreciated the functionality to mark video position while commenting and to playback marked video clips while reading other's comments. They also thought the peer assessment activities facilitated reflections on their teaching.