The Gear S has a pretty large (for a smartwatch), 2-inch curved Super AMOLED screen with a resolution of 360x480 (exactly 300 pixels per inch) and is powered by an unnamed dual-core processor, clocked at 1GHz, along with 512MB of RAM (which is pretty standard for smartwatches at this point).
The IP67-certified, dust- and water-proof device measures in at 1.57 x 2.28 x .49 in (39.9 x 58.1 x 12.5 mm) and both the Blue Black and White models weigh 2.32 oz (66 g). As already mentioned, the device also has dedicated Wi-Fi 802.11 b/g/n radio, but also Bluetooth 4.1 Low Energy and A-GPS with GLONASS support. Embedded within the body are also a whole bunch of sensors, including an accelerometer, gyroscope, compass, barometer, along with monitors for UV light and heart rate. With so much hardware packed inside, Samsung didn't have a lot of space leftover to fit in a large battery, so we're looking at a 300 mAh unit, which probably will require charging every night -- at least based on our experience with smartwatches so far.
There's one last caveat with the Gear S -- it's not making use of Google's new Android Wear platform, and is instead relying on a version of Tizen built for wearables. This might be a letdown for some, as Android Wear appears to be moving in the right direction (and is certainly getting more and more third-party devs on board) and Google Now is quite a bit more powerful than Samsung's S Voice platform, thought that might have been the price to be paid in order to give you a totally smartphone-independent smartwatch.
The Gear S will first launch on AT&T and Sprint on November 7 ($199 w/ 2-year contract or $16/mo. for 24 months, respectively) and, two days later, on T-Mobile ($14.58/mo. for 24 months). Verizon is confirmed to also get the gadget, but is keeping mum for now.