In a saucepan, heat the cranberries and water to the simmering point. Simmer for 15 minutes, until the berries have burst and the liquid takes on a syrup-like consistency. Strain mixture through a sieve; discard berry skins.
To hot liquid, add gelatin, sweetener, and 1 or 2 drops blue food coloring, stirring until dissolved. Pour into a 3-cup gelatin mold and chill overnight.
Makes 12 (1/4-cup) servings. Each serving is 1/4 fruit, approximately 11 calories.
NOTE: The reason for the blue food coloring is that without it, this cranberry sauce is very RED. If you want it to look more like the canned stuff (a purplish hue), just add a drop or two of the blue).