Hello oleg,
Recording sound and video is a little more complicatet than playing it back, as you would probably expect, but it is still fairly simple. There is just a little more setup to do.
Have a look here for the whole media-stuff.There already is a CameraPreview-Example provided by Google itself:
(click)but as long there is no way to associate an usb-camera with the emulator or test on an actual device it is not that useful.
Regards,
plusminus