I just bought the iPad version (there is an iPhone version too) – hey, it works! i3DSteroid is a Stereoscopic 3D Photo App for iPhone and iPod touch – 3D Vision Blog.
Unlike many 3D apps, this one includes automatic and manual image alignment. You can pull photos out of your photo gallery, both MPO and independent stereo pairs.
Once done with your 3D processing, you can also upload to Facebook or Twitter. Nice.