There were originally rumors that Venom would be the villain in Marc Webb's upcoming Marvel Comics adaptation, although The Wrap is reporting that Venom will not appear in the Untitled Spider-Man Reboot at all.
We reported back in June that The Lizard would, in fact, be the main nemesis. Ironically enough, actor Dylan Baker portrayed Dr. Curt Connors in both Spider-Man 2 and Spider-Man 3, although he never transformed into the villainous Lizard in those movies.
This news wasn't confirmed by Sony, though The Wrap does report that it was confirmed by two sources close to the production. We'll be sure to keep you posted as soon as this news is made official.