Damnit!
I really hope that's not true about Venom. I know most people would disagree with me, but I think he would be a terrible villian. Not in terms of himself being a poor character, but I just can't see how they could possibly bring him into the movie storyline, seeing as in the comic his origin is fairly long, drawn-out, and completely unbelievable.
So far the movie series, as much as being amazing and completely unplausable, has at its heart kept an semblance of believablity about it. Both the Green Goblin and Doc' Oc' were born out of failed experiments. Very much comic book, but almost something you could hang on to. Venom on the other hand..... Again I just can't see it happening. I also think that to have all these villians in the one movie is just too much. It would be impossible to develop all these characters as much as they deserve in just one movie. That is unless Sam is planning on making a 5 hour epic!
Personally I don't believe it. I can see the return of the Green Goblin (obviously) and The Lizard, seeing as the Dr Conners character has already been intorduced in SM2. However, I really do feel that Sandman and Venom would really spoil the series so far.
Anyway...
There are rumours that Grace has apparently signed for a fourth Spidey film, which if true could/would leave for more development of the Venom character. The favourite theory doing the rounds so far is that the film will include John Jameson returning from a space trip and Peter being assigned to take pictures (and Spider-Man getting involved somewhere). He'll pick up the symbiote which will probably help him defeat Sandman and The Lizard, but eventually have to give it up when it tries to take control. Parallel to this we see the story of Eddie Brock who always gets beaten to the job by Peter. The symbiote infects him and he becomes Venom. Right at the end of the film, we hear that raspy, harsh, slurp-esque breathing that Venom has...
Again though, it's all just speculation and fanboy talk at this point. Untill the actual release of the film we just won't know.