Hello,
I tested the Webcam support for VideoTexture. It works when I start the gameengine in embeded mode from the blender gui. When I start the Player in standalone mode (from gui or from commandline via blenderplayer) the texture will become just black and no image of the camera is shown. Playback of a moviefile works in booth cases.
I’ve made a small test blendfile, the webcam is hardcoded to /dev/video0, 25fps, 320x240. (I know ugly coding style 
)
I tested it under 2.64 and 2.65, they behave the same way.
(In earlier versions the webcam support was broken or only video4linux was supported instead of video4linux2, with a small patch changing from video4linux to video4linux2, webcam support was working in standalone mode)
Any Pointers are welcome.
camera.blend (492 KB)