Its been confirmed that Rhys Ifans is playing Curt Conners/The Lizard in the new Spiderman film according to Dark Horizons website:
"Though cast earlier this week, it was unsure what villain Rhys Ifans would play in the upcoming "Spider-Man" reboot at Sony Pictures. Well now it seems The Lizard will be his character according to The Wrap
In the comics, Dr. Curt Connors is a Florida surgeon who lost an arm during a stint in the army. Returning to civilian life as a research technologist, he tried to re-grow his amputated arm using an experiment in reptilian limb regeneration. The procedure worked but eventually turned him into The Lizard.
Dylan Baker played the role of Connors in the previous Sam Raimi-directed films. In that mythology he was re-imagined as Peter Parker's physics professor at University, but the actor never got the chance to portray the transformed version of the character.
There were rumors that Venom would serve as the villain in the Marc Webb-directed project, however the character is not going to show up at all apparently."