Surface is a 30-inch (76 cm) display in a table-like form factor, 22 inches (56 cm) high, 21 inches (53 cm) deep, and 42 inches (107 cm) wide. The Surface tabletop is acrylic glass, and its interior frame is powder-coated steel. The software platform runs on a custom version of Windows Vista and has wired Ethernet 10/100,wireless 802.11 b/g, and Bluetooth 2.0 connectivity. Surface applications are written using either Windows Presentation Foundation or Microsoft XNAtechnology.

At Microsoft's MSDN Conference, Bill Gates told developers of "Maximum" setup the Microsoft Surface was going to have:

Intel Core Quad Xeon "WoodCrest" @ 2.66GHz
4GB DDR2-1066 RAM
1TB 7200RPM Hard Drive
It has a custom motherboard form factor about the size of two ATX motherboards

Windows Presentation Foundation:

The Windows Presentation foundation is a graphical subsystem in.net framework.3.0. which uses a markup language, known as XMAL, for rich user interfacedeveloment. WPF is included with windows vista and wndows server 2008 and is also avialable for windows XP service pack2 or later and windows server 2003. It aims to unify a number of application services: user interface, 2D and 3D drawing, fixed and adaptivedocuments, advanced typography, vector graphics, raster graphics, animation, data binding, audio and vedio.

Here's the video of Table Top.