Mix together cream cheese and sugar.
Set aside.
Place pretzels and melted margarine in the bottom of a 9 x 13 baking dish and bake at 400° for 10 minutes.
Cool slightly.
Spread cream cheese mixture over lukewarm pretzels.
Spread whipped topping on top and cool.
Dissolve Jell-O in boiling pineapple juice.
Stir in strawberries and allow to thicken almost to jelled point.
Spread over whipped topping and refrigerate.
Cut into squares and serve.