Go to the nearest KTV and ask them for some popular songs. You will get them along with subtitles and video 🙂 Some persuasion might be required though.
Phone apps are good for that too but small screen will kill your eyes in no time.
P.S. You can actually try and get KTV whole database but god only knows how large the thing is.
P.S.S. While it can help you to speak Chinese, i STILL cant sing a single song on it… T_T