Xperia S is a powerful phone which comes with very nice hardware and software combination, It runs on Android 2.3 aka Gingerbread version, Sony promises that it will release ICS update for it in Q2 of 2012, means you will get ICS update till June.
It has a 1.5 GHz Qualcomm Dual Core processor which makes work on it very smooth, It has 4.3 inch scratch-resistant TFT touchscreen which has 16 million colors and 1280 x 720 pixels, The screen is quite bright and responsive.
One interesting thing in this phone is that it has a transparent bar at the bottom which will change its color according to the most vibrant color on the screen.
At the back of phone you will see a 12.1 megapixel camera with LED flash and Auto focus, which has 16X Zoom support. You can shoot 1080p HD videos using it. You can view BMP, GIF, JPEG, PNG, and WBMP, On the other hand all captured images are in JPEG format. You can view and capture your videos in 3GPP, MP4 formats.
If we talk about front facing camera then its 1.3 MP camera which support 720p HD, means you can make HD calls to your friends. In terms of connectivity it supports USB 2.0, Mini USB, WiFi, HDMI output, Bluetooth, aGPS and NFC technology and a 3.5 MM jack.
It has a internal memory of 1 GB which can be extended to 32 with the help of memory card, It also has a 1 GB of RAM, It supports GSM GPRS/EDGE and UMTS HSPA network protocols.
In total this is a quite powerful phone launched by Sony here in India, it will cost you around 32K INR.