My son did the same thing when he was two years old. His tantrums ALWAYS seemed to last 45 minutes to an hour, and he would scream, kick, hit, throw things, etc. It's fun, I know.
Two things worked for us. First, I read many sources that suggested having a tantrum as loud and as dramatic as that of the child, because the child will then be focused on your tantrum, rather than his own. Usually our son would start to laugh at us, then giggle, then we'd all have "funny" tantrums. I also made up a little song in which I sang and stomped my feet about how mad I am. It seemed to lighten things up.
On a more intellectual level, we also read a lot of stories about emotions and anger and feelings and all. There are a number of books out there, and they gave my son the verbage for what he felt, and it made him understand that what he was feeling is normal.
Hope I've helped. I really do know your pain. Good luck!