RealD Inc., in association with FrameForge Previz, have released an iPhone/iPad pre-production tool for filmmakers shooting in stereoscopic 3D. The RealD Professional Stereo3D Calculator can be used to calculate parallax and separation to plan stereo 3D depth and help determine optimal rig settings and lens configuration. Sounds interesting, but the downside is that it's not inexpensive: it's $299.99 at the iTunes store.
I didn't buy/download it, so it's difficult to report on functionality or whether it really seems worth that much!
The blurb for the product says that users can select the display size upon which the content will be shown, the camera, its lens or lenses, and customize the rig and camera capabilities and parameters. The Calculator factors together these settings and reports how subjects will look in 3D.