Layer 1: Combine crushed pretzels, butter and sugar in a 9x13 baking dish. Bake at 400 degrees for 10 minutes, then refrigerate for 2 hours.
Layer 2: Cream together cream cheese, Cool Whip, and sugar. Pour on top of pretzel crust, and refrigerate for 2 hours.
Layer 3: Combine the Jell-O and boiling water, then add the cold water and stir until the Jell-O has dissolved. Add the fresh or frozen berries, the pour on top of the cream cheese mixture and refrigerate until Jell-O has set. (It took about 2 hours for mine to set.)
Cut into bars and serve!!