Dalai Felinto has committed his long awaited 'Multi-View' code. Multi-View will add support for stereo view using a variety of devices to Blender: with the proper hardware you will be able to render AND edit in full 3D!
— Dalai Felinto (@dfelinto) April 6, 2015
Supported hardware starts with simple anaglyph glasses (like red-green), but also supports interlaced displays, shutter glasses and side-by-side rendering (I suppose this means Occulus Rifts?).
The code is now in 'Trunk' which means you can either compile Blender yourself with this feature, or get it in a nightly build from the Blender Build Bot.
The full documentation is already available from Blender.org.