To answer Sel, the first video was sung by the two performers shown in the video, atop the globe in the opening ceremony.
The Girl who lip-synced, but did not actually sing the song, was nine years old. I could tell she wasn't actually singing the song during the opening ceremony, but I thought they at least were using her voice. Unfortunately they weren't.
I suppose the Chinese party officials who made the decision to do this were unfamiliar with free press, and therefore wouldn't have known what a ravenous pack of piranhas the International press can be when you give them something like this to harp on about.
Still, I was thoroughly impressed by the opening ceremony. The fire works and various dances and demonstrations, and the wire work was most impressive at all.
I cannot imagine another country ever doing a better job, for all the brouhaha over lip-syncing and foggy fireworks displays. It was truly a new level, a new standard has been set.