Sprint Premier customers are being treated to a rather tantalizing account alert tonight: "Visit us tomorrow for an exciting announcement about a groundbreaking new device." No other details provided, but if we had to make an educated guess, we'd say all signs are pointing towards HTC's Supersonic, the long-rumored WiMAX smartphone with a 4.3-inch screen and Android 2.1 with Sense UI. A 4G device would certainly fit the billing as "groundbreaking," and we've already
