Bororo 3D is a plugin for Sony Vegas and any other video editor that supports Sony Vegas DirectX plug-ins.
It allows you to composite the left and the right video streams into a single stereoscopic stream, such as anaglyphs viewable with 3D glasses, videos interlaced horizontally (as in field-sequential DVD) or vertically or in a checkerboard format, left/right suitable for YouTube 3D format, above/below, as well as left-only or right-only. You can produce predefined anaglyphs or create your own anaglyph format.