Here it is, the Cubemap Splitter utility! You can use this to split any of the Cloudy Skyboxes or Planet Surface Skyboxes into their 6 individual frames, or convert between Cubemap and Panorama. You can also select and import 6 individual frames again and re-stitch them into a Horizontal Cross Cubemap (4:3) or Equirectangular Panorama (2:1)
Thanks. The reason I needed the sides separate is because I want to use them with a new n64 game engine that just came out called pyrite64, it has a special render mode that allows you to use textures up to 256x256 so i needed to split the cubemaps into the 6 sides and scale them down by 50% with imagemagick, the scaling part is easy, it was just the splitting that was going to be kind of tedious due to how many skies there are in the pack