Microsoft announced its own tablet device today, the 10.6-inch Surface Tablet. Microsoft is taking a huge leap with a mobile-friendly tablet, built on its new Window 8 operating system, which rolls out this fall. The Microsoft Surface and Microsoft RT tablets will be built in-house. The company is stepping into the tablet market at a critical juncture when growth in PC sales is slowing and consumer interest in iPads is soaring. Even some tablets built on Google’s rival Android mobile operating system, such as the Amazon Kindle Fire, are selling strongly.

Wrapped in a magnesium case that Microsoft calls VaporMg, the highlight feature of the Surface tablet might be its magnetically-attached cover that folds down and functions as a full touchscreen keyboard.

The new Microsoft Surface will feature a 10.6-inch wide display with Gorilla Glass, its own stand, a full-size USB port, dual Wi-Fi antennae, a multitouch keyboard, a trackpad — and yet is only about a half-inch thick, says Windows chief Steven Sinofsky. Models will come with either 64 gigabytes or 128 GB of storage.

“With Windows 1.0, we needed the mouse to complete the experience,” said Ballmer. “We wanted to give Windows 8 it’s own hardware innovation. Something new, different, a whole new family of computing devices from Microsoft.”

There will be two options for Microsoft’s Surface PC, one powered by Intel’s 22nm Ivy Bridge chips running Windows 8 or a Surface powered by an ARM chipset and Windows RT. The Windows RT version is just 9.3mm thin, weighs 1.5lbs, includes a built-in kickstand and is the first PC with a vapor-deposited (PVD) magnesium case, according to Microsoft. It will ship in 32GB or 64GB versions, complete with a 10.6-inch ClearType HD display.

Microsoft’s Intel-based Surface tablet will run Windows 8 Pro, with a thickness of 13.5mm, a weight of 1.9lb, and USB 3.0 support. This particular version will also include magnesium casing and a built-in kickstand, but will ship with either 64GB or 128GB storage. The Intel version will include additional digital ink support through a pen that magnetizes to the body of the tablet, and a 10.6-inch ClearType Full HD display. Both of Microsoft’s Surface tablets feature optional Touch and Type covers.

Microsoft says suggested retail pricing will be announced closer to availability and is expected to be competitive with a comparable ARM tablet or Intel Ultrabook-class PC.