What would you suggest for a person just starting and learning to use mods and altering the gameplay. Is there a download that is good for a beginner that is easy to understand and takes you through each step? I think I'm ready to start altering the gameplay and the game files. Thanks.

There are several articles both in the Tutorials, Referance & Guides forum, and at the top of this page. The Modder's guide to Civ 4 is also quite good - http://forums.civfanatics.com/showthread.php?t=132476

If you need any help with anything, there are pretty much always people on this forum willing to help with any question - just make sure you give as much information as possible otherwise they might find it quite hard to help.