Heat water in the microwave until hot.

Stir sugar-free lime gelatin into the hot water until dissolved, then set aside to cool.

In a mixing bowl, blend Splenda, fat-free cream cheese, and half-and-half until completely mixed and smooth.

Add lime juice concentrate and the dissolved lime gelatin mixture to the cream cheese mixture and mix well until fully combined.

Pour the mixture into an empty pie pan or a prebaked graham cracker crust if desired.

Chill in the refrigerator for at least 4 hours, or until firm.

Alternatively, pour the mixture directly into parfait glasses for individual servings.

Serve chilled, optionally topped with whipped cream.