So, you want to put your 3D videos on YouTube and you would like to be able to access all those cool 3D options, but you haven't been able to find any info that tells you what to do.... well, let me pass on what I have found out so far.... not much, but better than nothing.

First, to be able to see the 3D options, it appears that you need to be viewing the video on the YouTube site. It doesn't seem to work for embedded videos ( if you know how to make 3D work with embedded video please let me know! ). Go here to see the original on YouTube. 

Then you need a stereo movie that you have prepared in side by side mode and have saved to YouTube. Now in the "Video Information" section either of the upload page or the "edit video" option of the YouTube header menu, you add the appropriate tags..

The available tags are :

yt3d:enable=true Enables the view mode. 

yt3d:aspect=3:4 Sets the aspect of the encoded video.

yt3d:swap=true Swaps the left and right sources. You may need to add this to videos when the player with fixed anaglyph modes ships. Apologies for the inconvineince.

yt3d:left=0_0.1_0.5_0.9 and yt3d:right=0.5_0.1_1_0.9 These tags are very provisional and most useful for fixing up old videos. They set the source area for each eye as pairs of coordinates x1_y1_x2_y2. The scale of these coordinates is 0,0 for the the top left down to 1,1 for the bottom right.

For my video I used the (yt3d:enable=true)  to give the stereo option and (yt3d:swap=true) to swap the left and right eyes so that the anaglyph options would display correctly. I believe there is a bug which currently causes the eyes to be swopped.

Hope this helps and look forward to seeing your 3D videos on YouTube.