Sam Raimi confirms the meetings have begun.  EmpireOnline chatted with Raimi at ComicCon this past weekend.  He didn't say for sure that he was directing, just that he was open to the possibility.

"I want to help contribute to the production,” said Raimi. “I don’t know if I’ll just be a producer on it but if I can work with the writer in such a way so that directing would be right for me, I don’t know. We’ve had our first meeting on 'Spider-Man 4' and we're looking for the writer."

Early rumors had pegged David Koepp ("Spider-Man," Indy 4) as penning the next installment, so anything is possible at this stage.