Want to develop mods using the ModAPI? The Spore ModAPI Development Kit allows you to program mods with C++ for Spore.
Here you can download the Development Kit that contains everything you need:
There’s an online documentation which you can check for information and tutorials: http://davoonline.com/sporemodder/emd4600/SporeModAPI/index.html
There is also a tutorial on how to install the required tools and create a basic mod: ModAPI Tutorial: Installation and basic mod