Here's a nice tutorial that teaches you how to create your own planet using your panorama photos with the help of Photoshop. Crop your photo to make left and right border fit. Rotate it 180° and then rescale into a square image. Use "Polar" Filter and then do some digital editing to hide the stitch borders. Simple aye? Once you have created your own planet, you can post it on Flickr and add it to the Create Your Own Planets photoset.