According to car website "Edmunds Inside Line" :

SANTA MONICA, Calif. — Sources close to the production of the three films in The Fast & The Furious series have told Inside Line that a fourth installment is on its way. The best guess is that it will show up in theaters worldwide during the summer of either 2008 or 2009.

The project is currently classified merely as "in development" at Universal, with no clear production start date and no announced director. However, we're hearing rumors that the next film will reunite many characters and actors from the first three including Vin Diesel, Paul Walker, Tyrese Gibson and Lucas Black. Obviously the story will once again center around automotive mayhem of the most intense sort, but the rumor is that this time most of the action will be set in Rio de Janeiro, Brazil.

As to the cars, expectations are that some familiar machinery — like a resurrected version of the blown 1970 Dodge Charger from the original film — will mix it up with such contemporary machinery as the new Dodge Challenger and classic South American muscle like the Chevrolet Opala. Also don't be surprised if Vin Diesel's character finds his way behind the wheel of a classic 1987 Buick GNX.

Well Vin Diesel's career is going nowhere fast, so it would be no surprise if he signed on for this drek.

If a decent director is attached it may work as a popcorn flick.
I won't hold my breathe.

Please for the love of god make it stop, I guess Vin Diesel doesn't have any good movies in the pipeline anymore so why wouldn't he come back to this.

I actually really liked Tokyo Drift, so as long as they try to take it more in that direction rather than the steaming turd that was 2 fast 2 furious, I would probably go see it.

I've liked all 3 so far. I'd watch a 4th, especially with all the returning characters if true.

I love this franchise so this is great news that there will be another movie, even better if all those guys really do end up in it.

Not going to lie, as much as a movie snob that I am, this franchise has been a fucking blast up to this point. I'm down for a fourth installment, especially if they could wrap up all the characters and storylines from the past three films.

Is this going to be like F&F meets City of God?

They would have been better off if they had made the world of street racing more like the world of street racing. I spent my teens on Glenoaks and Peoria and Coldwater in Los Angeles. Street racing isn't even close to these movies. Rarely did something running under 12 seconds make an appearance. My Civic was turbocharged and that was fairly uncommon.

It's about time. It's about fucking time.

Hopefully they'll have more action in this than Tokyo Drift. Racing cars inside a parking garage might look cool, but the first F&F sounds the best coming out of my speakers. Let the cars be the stars, we already know that Paul Walker is going to walk away ok at the end.

I thought the first one was a good popcorn flick, the second one wasn't so good and I skipped the fourth. I might catch the fourth on cable one day but if the movie is indeed called 4ast and the 4furious then I'm going to have to get a movie poster because thats the best name for a sequal ever.

I'd be up for this. I really enjoyed the first two, and after some hesitation, watched the 3rd and surprised myself by enjoying it as well.

If Vin is hard up for work, they should work on another Riddick movie, I want to see them go to the Underverse.

I’m not a big car enthusiast but I enjoyed The Fast & the Furious & 2 Fast, 2 Furious wasn’t as horrible as some critics made it out to be, I thought it was fun. I haven’t seen Tokyo Drift yet.

If they bring back the original cast from the first one or have both mix it up having cast members from the first & second, I’m in for it. Vin Diesel better come back for this one, he hasn’t done much lately so I really hope he signs on for 4ast and the 4urious, BEST.TITLE.EVER.

4Muney and 4Prophit!

The Fast and the Furious Forever / The Fast and the Furious 4Ever

I hope there's a near brawl over a tuna fish sandwich again...

I still think the best line from the original is:

"You think you had me? You never had me! You never had your car!"

My friend and I would repeat that line about ad nauseam when we played Halo together.

Fast and Furious 4- Big Booty edition

Drift was better than the first two movies IMO. I'll watcha 4th film.

Count me among those that found Tokyo Drift entertaining. I would be in for a 4th installment as long as they maintain that vibe. Part 2 stunk to high heaven.

I'll be there...

... to make fun of anyone buying tickets. I mean, seriously, this sounds pathetic so imagine how it's going to look. I'd ask where Diesel and Walker went wrong, but, oh, where to begin?

I loved how Drift brought something new to the table. Hopefully, the 4th installment will do the same.

Yes, this would be a perfect project for Fernando Meirelles or Hector Babenco.