M.L.
My (two year old) daugher takes her time outs in her room. If the time out is simply for yelling or crying, I put her in her room, with the door ajar, and explain that she can come out as soon as she's done crying or ready to ask nicely for whatever she wants. (I'm not PUNISHING her for crying...she can just come back when she's done!)
If it's for something worse, like hitting, pinching, etc., she goes into her room, with the door closed...and a baby-proof door knob. She can cry and scream all she wants, but she has to stay there for the allotted amount of time (usually the time it takes me to walk back out to the kitchen, calm myself down, and go back down the hall and get her.)
I hope that helps. The other thing that works for me (and it may just be because it happens to work...) is that, when she's naughty, I get right down in her face and ask her to look at me. If I really just need her to calm down, I put my face next to her ear, hold her head to my head, and talk very quietly. She'll usually stop yelling long enough to see what it is that I'm saying. She's a very PROUD child and can't stop screaming JUST because I tell her to. She needs a time out, or a snuggle, or SOMETHING to just reset!