From the YouTube Creators blog, YouTube now has a way for you put music to your videos without the risk of them being pulled for licensing violations. "When you’re uploading a video to YouTube, knowing where to search for the perfect song can be tricky. We do our best to provide creators with tools to enhance their content and to simplify this process, but we wanted to make it even easier to find great music for your videos.
That’s why we’re launching the the YouTube Audio Library today. Any YouTube creator now has access to more than 150 royalty-free instrumental tracks you can use for free, forever, for any creative purpose (not just YouTube videos). You’ll find a link to the library in your video manager and you can browse the tracks by mood, genre, instrument and duration. The tracks can be downloaded as 320 Kbps MP3 files."
source: YouTube Creator Blog