We have been developing a system named "mutual telexistence" which allows for face-to-face communication between remote users. Unlike most conventional tele-conferencing systems which limit the users' viewpoint to a fixed position, mutual telexistence system should provide the images of the other users corresponding to the change of a user's eye position in the computer generated three-dimensional space.
http://www.star.t.u-tokyo.ac.jp/projects/mutel/