The following is a success story.
I read in one of the positive discipline resources (can't remember which book or if it was on the internet) the technique of saying "I need your help" instead of trying to MAKE her do it... I was skeptical but tonight was a REALLY rough night, she was overtired and after bath she was just crying and would not hold still. I tried putting her on the diaper, I tried distracting her with a balloon, I tried giving her a book to read... she ran off and climbed up on the couch. So, figuring I had nothing to lose, I took a deep breath and said, "Leni, mommy needs your help!" (she looked at me skeptically) "You need to wear your jammies, but I can't put them on unless you help me. Can you show me where your arm goes?" (she looked curious but I wasn't sure if she was going to go for it) "Does your arm go in here?" (I held up the sleeve and she reached her arm out and smiled). Then I asked her to show me how to put a diaper on and I slid the diaper under her, and she laid still and said "snap" when I snapped it on her... then I put one leg in her jammies, and she put the other leg in herself and said "ZIP!" and I zipped them up! By that time she had a big grin on her face!
I just had to share because I was SO amazed it actually worked!