There are few paid video recorder available in iPhone. I tried one of them but was not happy with the quality and it takes too much time in saving video to the disk. Recently I tried cycorder, which is available free of cost. I like this recorder as it doesn’t take time in saving video. Quality of recorded video is awesome. You can’t expect better quality than this in 2 M Pixel camera.
To install cycorder, you must have jailbroken iPhone which is running firmware 2.0 or above. Go to cydia search option and type cycorder. Now install it like you installed other packages using cydia.