"Well, I really tried my best to end the story of Andy and his toys and bring that story to a close in a really nice way at the end of this film. That being said, we know that people love the characters, love Woody and Buzz, and would hate to say good-bye to them completely. I don't know that there would ever be a [Toy Story 4]. We don't have any plans for one -- but we are trying to find ways to keep the characters alive. We have announced we're going to do a short film in front of Cars 2 that uses the Toy Story characters. We're going to keep them alive; they're not going away forever."
So that's good. I guess they don't die at the end of the new movie, then? As if! (In honor of the release of Toy Story 3, I'm bringing back slang from 1995. Later maybe I'll use "mad props" and end an incorrect statement with "NOT!"). Hopefully this is a matter of them wanting to entertain the fans and not about them running out of ideas for more original shorts (and features -- Pixar does have an awful lot of sequels in development, after all). Either way, I'm sure I'll never get tired of or complain about too much of the Toy Story characters.
Coming from someone who really disliked the first Cars movie (it was "whack"), I hope to have an opportunity to see this short without having to buy a ticket to or rent Cars 2. That said, I do admit to being hopeful the minds at Pixar are crafting a sequel that more than makes up for the disappointing elements of the first Cars. As TS3 will show you (and Toy Story 2 did before), the studio does have that rare talent to make sequels as good as if not better than their originals.