I did a little about this at university ----technically it is against copyright law to use/distribute any copyrighted music and put it on your tube etc. But it happens all the time and its not being sold, or is not in high quitlity so artists let it go - as once the artist finds out there has been a breach of copyright, it is them that has to make most of the decisions of whether or not to make charges - so the liklyhood of them chasing things up on your tube is very low, and perhaps wouldnt even stand up in court as there are so many others comitting the very same (minor) offence at the same time...
yes in theory it is against the law, but copyright is such a huge topic - its like saying finding a pound on the floor and not giving it back, is the same as an armed robbery!!
I use copyright music all the time in my university projects - I think students and teachers should be more worried about the student making sure they reconise copyrighted music in their work, rather than being worried about keeping on the :very blured: right side of the law.
I find it very hard to see how putting a piece of music in your video projects and posting it on your tube, as long as the music isnt pre-realese or in someway specail, can lead to any major charges being bought against you.. I think if the music industury sued people out of princable then it would be a very different story, but you have to remember that the music industury has no prinicables!! because there will always be more people breaking the law than those who can inforce it they must go after the 'armed robbers' and not the 'petty theives'...
in short - it is illegal, and I think we all (most of us) agree that things like the file sharing of software like premire is wrong(ish), but much of it is down to more of a socail acceptance, - this ofcourse can never change the law, but it somehow makes us overlook it..this and the fact that the music industury wouldnt make any money bringing charges against these type of things, I think is the main reason that you can :kind of: get away with it...
But i would never do it as Ive got to many morales!!!!