Preheat broiler. Combine ravioli and garlic powder in large microwave-safe bowl; cover with microwave-safe plastic wrap. Microwave on HIGH 2 to 3 minutes or until mixture is hot. Carefully stir in tomatoes.
Divide mixture evenly and spoon into pita pockets. Top with cheese. Place filled pockets on baking sheet; broil 2 to 3 minutes or until bread is toasted and cheese melts.