YouTube has a new video editor that lets you create videos using excerpts from the videos you've already uploaded.
You can also add a music file from the AudioSwap library, but YouTube mentions that it might display ads if you use some of the audio files.
I tried locating the 'Editor' link or button on my account but could not find it. May be, the service is still not open officially.
But you can definitely access it using the following link. [More]