on a trip to my sister's house it started acting up after I called her to let her know when I'd be there. After I hang up, the phone kept trying to call her back. I ended up pullng the plug on the headset cause it was getting in my way, and all of the sudden it stopped trying to redial.

What the headset had to do with the cell phone redialing the last number, I don't know. I've since gotten a new headset, and the problem hasn't repeated.