This is just a re-upload to the nexus from ModDB. 
http://www.moddb.com/games/spore/downloads/betterspore-151

There is a readme included that describes the features of the mod as well as manual installation procedure.
As Merazul has pointed out, Spore has a modding tool called SporeMaster which is generall recommended over manual installation. Here is a wiki page detailing the program and a guide to using it.

The readme can be read on the nexus page as well in the Docs section.