I hear the film was based on a few different interpretations of the flood myth and would love to learn more about these types of myths without the religious angle (i.e. the implication the myth is true)
Here's a site with not only a cornucopia of flood myths from across the world, but a complete reference list to their sources.
The closest alternate version for Noah to the Genesis account is the Epic of Gilgamesh, of which you can read a translation online here..
Is there anything particular you are interested in knowing, or do you just want some sources to follow?
You may also wish to look at Y.S. Chen's The Primeval Flood Catastrophe: Origins and Development, which traces the history of the flood myth in Mesopotamia and includes both the main mythological texts and references outside of mythological texts.