Preheat oven to 350 degrees F. Position the rack to the middle of the oven.
In a medium bowl, mix together the pretzel crumbs, sugar and butter. Press into the bottom of a 9x13-inch pan. Bake for 10 minutes. Remove from the oven and cool completely.
For the filling:
In a large mixing bowl, cream together the cream cheese, sugar and milk until smooth. Fold in the whipped cream, then spread the filling evenly over the crust. Refrigerate while you make the topping.
For the topping:
In a large bowl, stir together the boiling water and gelatin mix. Stir for 2 minutes, or until completely melted and the gelatin is completely dissolved. Immediately add the cold water and stir. Refrigerate for 1 to 1 1/2 hours, or until thickened. Stir in the sliced strawberries, then layer evenly over the filling in the pan.
Cover and refrigerate for 3 hours before serving. Best served the same day, or within 24 hours, but is still good up to 2 days later.