Add a soundtrack to your YouTube videos with AudioSwap
YouTube has rolled out a new feature called AudioSwap that allows users to add a music soundtrack to their videos after they've been uploaded to YouTube.
After you publish a video, click on the Replace Audio button on your My Videos page. From there it's a simple 2-step process of picking the song you like from YouTube's offerings (no worries about copyright infringement here), previewing it with your video, and publishing away. All of your previous audio will be lost (no huge problem if it's a computer demonstration or a noisy clip with bad audio to begin with), replaced by the soundtrack. I tried it out with a video I'm publishing later today, and it seemed to work without a hitch. — Adam Pash