Jack Enright’s Leo Frank Page A page about the case from Jack Enright, who did funded undergraduate research on the case.
Tom Watson: The Leo Frank Case An article by Tom Watson in his namesake Watson's Magazine, published January 1915. Published by The American Mercury, transcribed by Penelope Lee.
Here are some other websites with an opinion of their slant towards either Conley or Frank being innocent (or at least not the main perpetrator).
Leo Frank.org (pro-Conley)
Little Mary Phagan by Mary Phagan-Kean (pro-Conley)
The Leo Frank Case – open or closed? by Allen Koenigsberg (somewhat pro-Conley)
Leo Frank timeline (neutral)
Leo Frank Wiki (somewhat pro-Frank)
The Trial of Leo Frank: An Account by Douglas O. Linder (pro-Frank)