I was hoping it was a walkthrough on how to MAKE them. Its hardly rocket science to just crop an existing one to the right size. (although I could be wrong as I thought the N900 allowed you to use a single image not have to split it into four, which is a little more tricky)

Knowing the right term to search for to find existing ones (equirectangular) is helpful though, but I am going to have to search further on how to actually make them myself.

Actually, you do not need equirectangular images for the N900 but I do not know if there is a specific term for a seamless looping panoramic image. They are however a LOT easier to make than an equirectangular image though.