1. Place the strawberry ice cream in a medium bow; stir until smooth and spreadable. Spoon the ice cream into the pie crust and smooth to make an even layer. Cover with plastic wrap and freeze 1 hour.
2. Place the blueberries in a medium bowl. Mash berries with a masher or the back of a spoon. Add the vanilla ice cream; stir until smooth and spreadable. Spread the blueberry mixture in an even layer over the strawberry ice cream. Freeze until solid, about 8 hours or overnight.
3. Beat the egg whites and cream of tartar with an electric mixer on medium speed until soft peaks form (tips curl). With the mixer still running, gradually add the sugar, 1/2 Tbs. at a time until all the sugar is incorporated. Beat in the vanilla.
4. Remove the pie from the freezer and take off the plastic wrap. Spread the meringue over the pie, completely covering the ice cream. Return the pie to the freezer.
5. Arrange oven rack 8 inches from the broiler and preheat the broiler on high. Place the pie in the oven and broil until the meringue is lightly golden brown, about 2 minutes. Serve immediately, or freeze until ready to serve.