indeed it is!
make yourself a point_camera and set it up to point at wherever.
you may need to tell it to point at a target entity if you want it to move, etc. give it a name.
the viewscreen needs to be textured with dev_monitor or similar. just filter for 'monitor'.
only texture one side of the 'monitor' with the monitor texture, then tie to a func_brush. give it a name.
then make a info_camera_link and name it.
set "entity blah blah" to the func_brush and "camera" to the camera name and it should be all good....
anyway i got that info from
madcow's tutorial so if its wrong blame him
edit: and to make it move set the 'parent' of the func_brush to the entity you want to attach it to