Raeivet

Last year I remember watching a Forza 3 video using a song found from OC Remix and thought it was awesome. Now I'm making my own Skate 3 videos and recently used a John Mayer song and I'm terrified if I keep using songs by big record company's I might get sued or something. So my question is if the music found here can be used in my videos? Do I have to contact the artist?