Wow…I think we hit the motherload when it comes to Spore information.  You can find a thread at  GamingSteve’s forum which shows off a ton of hidden information including text files of many details regarding Spore as well as images that were hidden.  All of this information was pulled from the Creature Creator.

Why did Strongbad make it in there?  Guess someone was a fan!

You can also find the text files with tons of spoilers over at this website.