CRUMB CRUST: Mix together Oreos and butter and press into 10 inch springform pan.
FILLING: Cut cream cheese into 1 inch cubes. Beat with mixer on medium speed until smooth. Add whipping cream and vanilla. Beat well (about 10 minutes). Very slowly add sugar and then add eggs one at a time beating well between each addition. Remove 1 cup batter. Add peanut butter to remaining batter and mix well. Spread in pan. Add chocolate to reserved batter. Swirl into peanut butter batter.
Bake at 350 degrees F for 30 minutes; reduce oven to 325 degrees F for 30 minutes then open oven door and bake for 30 minutes more (with oven on).