Marvel's Avi Arad was recently interviewed by iFMagazine. The Q&A with Arad included a handful of questions about the Spider-Man 3. One of his responses gives some insight on the villains from the upcoming movie:
iF: There are four villains this time, Venom, Sandman, and Green Goblin and when is the fourth going to be revealed?
ARAD: Right we have four villains. Pretty soon [we'll reveal the fourth villain] I believe. Maybe around Comic Con we'll reveal something and the madness will begin.
The entire iFMagazine article can be read HERE.
Spider-Man 3 was released May 4th, 2007 and stars Tobey Maguire, Kirsten Dunst, James Franco, Thomas Haden Church, Topher Grace, Bryce Dallas Howard, Rosemary Harris, J.K. Simmons. The film is directed by Sam Raimi.