S.,
My daughter will be 3 in four days and I have the same problem. Her father and I seperated before she was born and he was not very active in the first half of her life but now has visitation with her once a week. I have to prepare her hours in advance or she throws tantrums because she doesn't want to go and when she comes back she is so out of control I swear I need a sedative by the time the day is over. There have been times when he won't even take her out of my house because he says he doesn't know how to deal with her behavior. She is fine as long as she's home. There is no one set way to deal with this although many people have offered good suggestions. What works for me: when he brings her back and she's agitated, I take her for walks or read stories to her or let her color, anything that she enjoys, things that soothe her and allow her time to calm down. I start telling her the day before a visit that her daddy is coming. By the time he actually gets to my house she has already made her objections and is ready to go peacefully (for the most part). I make special plans with her for when she comes back ("when you come back from daddy's house we'll make cookies or go to the movies, etc.). Nothing works all the time. It's frustrating but you have to be patient and firm, reassuring and comforting. You'll make it through, just hang in there...it's all any of us can do!