Native support is being worked on for the 3D API, which shall be stable as of the 1.0.0 release for the next version of Adobe AIR. The most recent release of Pixel Bender 3D had preliminary support for 2D Object and Pixel Bender Triangle-Patch textures, with future releases adding support for Blitting and video support.
Pixel Bender 3D is available as an extension (under the Pixel Bender Extensions naming scheme), which provides access to the scripting interface, a simplification of 50e0806aeb