First you need to know why the tantrum is happening. Like said below, if it's because of teething a little Oragel will do the trick and a big hug. If it's because of bad behavior like doing something he shouldn't have and you've already said "No" and have given plenty of warnings, then a pen is the best place. Not a sleeping pen, but one of those pens you snap together like locking gates. Place him in there and when he's done and has calmed down then take him out. And too while he's in there totally ignore him with quick glances to make sure he's safe. First I had the pen in the living room. Then when that didn't work anymore, I moved the pen to his bedroom, left a light on, and left the door open. Also make sure there is nothing in the pen with him...no blanket...no toys...nothing. It's the best thing in the world to use. Of course when he gets too big for the pen, then move to a time-out chair/area.
My son started using the "Trouble Pen" at 10 months. It's never too early to start. His teacher says he's very well behaved at school. And now when he knows he's done something wrong he volunteers himself to timeout. It's great! But sometimes when my 3 year old son has his moments he still has to go to the "Trouble Pen" when he's totally non-cooperative and when he's out of control.
Just stay on top of it and stick to your guns. It will pay off! Most of the time all I have to do is remind him of the "Trouble Pen" and that's it and he moves on. He's not quite done with his tantrums, but they are getting less and less as time goes by. He just needs to be reminded who's the boss every once in a while.