The iPhone 4S is the follow-up to the very popular iPhone 4 and features a faster Apple A5 dual-core processor and improved 8 megapixel camera. The iPhone 4S also features Siri - a voice assistant heeding natural-language questions and commands and taking dictation. Other features of this smartphone include a gorgeous 3.5-inch high-resolution display full web browser Bluetooth compatibility music player WiFi and 16 GB of internal memory. The iPhone 4S also comes equipped with quadband GSM CDMA and WCDMA modes for international use.