Google hotspot shield, its ok for a free service, there are also anonymous sites that shield your ip for you bouncing you from server to server (costs money, free ones suck), if you want to hide your ip, the best thing to do is find an unsecure ip address via wireless router, and use it with a clean laptop with no trace of your name, cookies, etc... on the laptop. Please note i do not condone this for illegal use, but if you want to watch some weird legal porn or whatever this is your best bet. If they ever trace the ip, they will never find you
Remember, your IP address is linked to your account for your internet, all gov does is call up provider, give ip, and they got your home address