The inclusion of Venom in Spider-Man 3 wasn't handled very well, by any account: Sam Raimi was apparently asked to include the villain over his objections by Sony, and it was fairly poorly done. The symbiote appears early in the film, then simply disappears for an hour until the movie needs to have another villain, on top of the two that already existed. The movie wasn't very good, but I guess that, in the end, Sony achieved their goal of ensuring that the bulk of the movie-going world at least knew who Venom was after they had seen the film.
That groundwork, having been laid, might soon be built upon, as the L.A. Times says that Sony is talking with Josh Trank, the director of Chronicle, to shepherd the project to the big screen. That makes sense, if you think about it; The Amazing Spider-Man was rebooted to lower costs on the Spider-Man films, and Chronicle proved that Trank has the talent to release a superhero film without breaking the bank. It's likely that they'll wait to see if Amazing does well at the box office before committing to the project, but the for the moment it looks like it's in the works, as it has been off-and-on since 2008 at least. According to the Times, Topher Grace wouldn't be expected to reprise his role as Eddie Brock, but that's hardly surprising.
The question now is how you approach the material; obviously the Venom symbiote tends not to create the most sympathetic characters, and obviously if the resultant film was anything like the awful guyliner sections of Spider-Man 3, we'd have problems. I'm not incredibly up on the history of Venom, but it'd be interesting to see if the film went as dark as the material probably could go or made the character more of an anti-hero. I'd bet on a tone similar to the first Punisher movie, myself.