Actually you know iPad just can play .mp4, mpeg-4, h.264, etc. videos, so if you wanna play divx or xvid video, have to convert video into the certain format that ipad supports. Third program may help you a lot.
i personally used iMacsoft iPad video Converter tool, converts any videos, dvix, xvid, flv, wmv, avi, rm, etc. into iPad screen. Hope it helps you!