Make Interlaced 3D

Produces an interlaced (interleave) picture for viewing on polarized-mask 3D monitors. Supports horizontal and vertical interlacing, depth correction offset, field order, anaglyph and side-by-side (cross-eyed) source conversion. The "Depth correction offset" feature (sometimes called "parallax") makes the picture look deep beyond the screen surface.

v1.5: Added the "Convert to grayscale" options: "Do not convert", "Simple" and "Better (with hi-pass filter)" (the hi-pass filter diameter is adjustable); and the "Post-equalization" option. Both of the options provide better anaglyph to interlaced conversions.
v1.4: Added the "Source type" drop-down box with three options: "Two Layers", "Anaglyph" and "Side-by-side"; the "Resizing options" box: "Do not resize", "Fit to screen height" and "Fit to screen height and crop"); and fixed a couple of bugs.
v1.3: Added the following new self-explanatory options: "Your screen width" (default=1920), "Your screen height" (default=1080), "Convert to grayscale" (very useful with b/w anaglyph sources), "Crop to the screen width" (turn it off for panoramas). Also the default "Depth correction offset" is now set to 0.
v1.2: Added the "Anti-aliasing" feature; Fixed the depth correction offset for left-right-swapped images.
v1.1: Added the "Anaglyph source" option. It allows the anaglyph to interlaced conversion.

Written in Python. Download, rename (remove the .txt extension), put it to ~/.gimp-[version]/plug-ins and make it executable (chmod 755). Open the image pair as layers and run the plugin from Filters/Combine/Make Interlaced 3D...