In 1954, Al Feldstein and Al Williamson adapted the story with EC Comics. Al Williamson was one of the greatest photorealistic artists in all of comics (the best, by my money) and he could draw a mean-lookin' dinosaur. The one element from the short story which was not maintained in this adaptation was the titular "sound of thunder" - the gunshot which concludes the story. Once again, we see EC exercising restraint. They printed more than just stories about baseball games with human organs, kids!
Although many Bradbury tales were adapted to the 1950s radio program X Minus One, "A Sound of Thunder" wasn't one of them. However, fellow sci-fi author L. Sprague DeCamp wrote a response to Bradbury's tale (as he didn't entirely like it) called "A Gun for Dinosaur" which was adapted to X Minus One, but that tale has fallen into obscurity. "A Sound of Thunder" even spawned its own official spin-off series with the "Ray Bradbury Presents" moniker.
In 1984 Bradbury 13 faithfully adapted the story to radio (listen to it at Youtube here). The television series Ray Bradbury Theater adapted it in 1989. As the TV show did not have a large budget it usually kept away from elaborate special effects. The dinosaur in that episode is clearly a puppet, but I think it's a convincing puppet; man, give me monster puppets every day instead of those drab CGI things.
Topps comics created a more faithful comic adaptation of "A Sound of Thunder" in 1993 with the great Richard Corben adapting. I would normally choose Williamson over just about every comics artist imaginable, but as Corben has the more faithful adaptation, I have to give him props; while Williamson mastered realism, Corben has a gift for starting out from a realistic perspective, then branching into utterly mad, wild imagery. Happily, Topps chose to reprint the Williamson story in the same issue as the new Corben version so everyone can choose their favourite.
Lastly, I am required by law to mention the 2005 film adaptation. That should do. Go read the Agony Booth review.
...Well... no, I have more to say than that.
It's a disaster; if you want a bad, cheesy sci-fi flick with lousy special effects and miserable performances, this is your baby. The story of the film's making is one of those great Hollywood disasters where studios are toppled and careers ruined. Edward Burns gives a bland lead performance while Sir Ben Kingsley, always a pro, hams it up and, as usual, makes you question his career choices. Bradbury's simple tale is expanded into feature length by discarding most of the short story itself, which is an odd way to expand the concept. In this version, time travelers don't return to the present to find everything changed - instead, time begins to slowly alter itself. For some reason, rather than history being changed so that the English language and political results are altered, these changes are somehow wiping out all of humanity (to raise the stakes) and reverting the Earth to a semi-prehistoric state (???). The film's would-be setpiece, the baboon-saurus is one of the lamest yet funniest movie monsters in all of cinema. They don't appear until very late in the film but if you can last that far, you'll be rewarded with some belly laughs.
More Bradbury tomorrow!