public synchronized void setFlashState(boolean state) {
		// If the camera has already been opened, we apply the change immediately
		if (mCamera != null) {

			if (mStreaming && mMode == MODE_MEDIARECORDER_API) {
				lockCamera();
			}

			Parameters parameters = mCamera.getParameters();

			// We test if the phone has a flash
			if (parameters.getFlashMode()==null) {
				// The phone has no flash or the choosen camera can not toggle the flash
				throw new RuntimeException("Can't turn the flash on !");
			} else {
				parameters.setFlashMode(state?Parameters.FLASH_MODE_TORCH:Parameters.FLASH_MODE_OFF);
				try {
					mCamera.setParameters(parameters);
					mFlashEnabled = state;
				} catch (RuntimeException e) {
					mFlashEnabled = false;
					throw new RuntimeException("Can't turn the flash on !");
				} finally {
					if (mStreaming && mMode == MODE_MEDIARECORDER_API) {
						unlockCamera();
					}
				}
			}
		} else {
			mFlashEnabled = state;
		}
	}
Turns the LED on or off if phone has one.
src/net/majorkernelpanic/streaming/video/VideoStream.java