Here are some safe steps for uploading video's with music.
1. Never add music that is not yours.
2. If your purchase music for play on your videos read the Company "Terms of Service" Plenty of companies have music for purchase.
3. Most Companies with royalty free music are very specific how to use the music purchased. Paying attention is important.. I purchase my music for my videos here Called the company and discussed how I would use the music and made sure I understood the "terms of agreement". Each song comes with a license with download. Terms of Service" are very clear how the music is used on videos for posting online. A license gives you permission to use within "terms of service".
4. Giving credit to the artist/band/label does not protect you. Adding a credit does not save you from a copyright violation.
5. Not sure? Be safe not sorry.. If your not sure exhaust making sure before you add music to any video you upload..
6. You can look at Stock20 for music. Before you do anything read the "terms of service".
I am not an attorney these are simple rules I follow. If you have questions about playing music contact your attorney. This is not legal advice. I simply say read all sites "terms of service". Ask questions? Call companies you purchase music through and ask more questions.
Here is some YouTube Info. YouTube has a audio library for adding music on videos. You can smaple song and download to your computer and add during edit. Must upload video to YouTube.
I help small business owners with cost effective branding using video online.
Update: Older video I talk about audio swap. YouTube now has a audio library for use of music on your YouTube Channel.