While we're on this topic, I thought I'd recommend a few books
First, I'm reading
Kingfish: The Reign of Huey P. Long. The author was at the campus bookstore last year and I chatted with him a bit. Its a pretty solid biography; every time you think Long can't do anything crazier than what he just did, just turn the page!
I'm also working my way (slowly) through
Huey Long's Louisiana Hayride: The American Rehearsal for Dictatorship. It mainly deals with the lasting ramifications of his legacy and examines why none of his successors were really able to continue the work that he started.