In a small saucepan, sprinkle gelatin over half-and-half; let stand 1 minute. Stir in sugar and salt. Heat and stir over low heat until gelatin and sugar are completely dissolved. Remove from heat. Add tea bags; steep, covered, 10-15 minutes according to taste. Discard tea bags.
Pour into six 4-oz. ramekins or custard cups coated with cooking spray. Refrigerate, covered, until set, about 5 hours. Unmold panna cotta onto plates. Garnish with fresh berries if desired.