My friend Dain informs me of this San Francisco Chronicle article suggesting that George Lucas plans to shoot the fourth Indiana Jones movie in 2007, with a spring/summer 2008 opening.
I'm unsure the working subtitle "The Ravages of Time" isn't meant to be tongue-in-cheek. Check out this picture of Harrison Ford:

He hardly looks any longer like the action hero we remember. Of course, if they could smooth out Patrick Stewart and Ian McKellan's wrinkles for X-Men 3, then who knows where that Pandora's Box will end. What do you think: is it time for Indy to pass on the torch? If so, will this be a "Son of Indy" tale? Should Sean Connery return to represent three generations of archaeologists? When should the story take place — 20 years after the last one?
I think Harrison Ford can pull it off still. They sure better set the story in the 50s or so though, or they've got some explaining to do.
To twist around what Sheppy said, as long as they don't try to ignore the fact that Indy (Ford!) isn't so young anymore, it could work. As long as the plot only requires Indy to use his brains and audacity, I think we can live with a lower level of personal physical action.
Maybe there could be a raw younger generation member (family or otherwise) to handle the physical stuff with lessons in how to use his most important muscle (the brain) from Indy.
I'd love to see Sean Connery again. Not that I think he adds anything specific to the Indiana Jones franchise, I just love seeing and hearing him in movies! :-)
Well, I actually think that Harrison Ford is still up to some mild action, but I agree he's not going to be able to pull off (at least not without looking silly) some of the stunts done back in the earlier films.
Supposedly, this film will be shot in the classic style that employs stuntment, not CGI. Perhaps Indy will just have more doubles in this movie than in previous ones.
Now Ford is insisting he's still capable of using a whip, and will pull out of the film if he's not allowed to.
Read the full story.
A 2007 production and 2008 release for Indiana Jones IV has been confirmed at both StarWars.com and IndianaJones.com.
Here's a round-up of recent news, right from Lucas, about Indiana Jones IV, including casting, timing, and trailers.
Courtesy Showbits reader GeneD comes this neat interview with Harrison Ford about returning to the Indiana Jones role and being a celebrity.