I found this in a magazine I was reading tried it and liked it.
1 graham cracker crust
1 8-ounce package cream cheese
1 14-ounce can sweentened condensed milk
1/2 cup key lime juice
2 cups Cool Whip, thawed
Beat cream cheese and milk until creamy. Beat in lime juice. Fold in whip cream until well blended. Pour in pie crust and chill.