Microwave cream cheese and peanut butter for 30 seconds, or until just softened. With an electric mixer, beat together everything except for the whipped topping until smooth. Fold in whipped topping.
Spoon mixture into prepared pie crust (if desired, you could reform the crust in a springform pan to make it more presentable). Refrigerate for at least 4 hours, or overnight.
You can also enjoy this peanut butter pie frozen! Simply place the pie in the freezer for a few hours, or up to one week, covered, and let it sit out for 10-15 minutes before serving!