Who is credited with inventing the fluorescent light bulb? Some resources told me it was Nikola Tesla, yet others told me it was a collaboration of Peter Cooper Hewitt, Edmund Germer, George Inman, and Richard Thayer. Can someone please clarify this for me? Thank you.

It was not Tesla. The other people you mentioned played a role at various times. A good history of the developnment can be found at:

http://inventors.about.com/library/inventors/bl_fluorescent.htm