For example, an article from the December 1900 issue of the Ladies Home Journal (as reprinted by a fascinating blog called Paleo-Future) posits that, in the year 2000, hot and cold air will be turned on from spigots (i.e. central heating and air conditioning); there will be airships maintained as deadly war vessels by all nations; wireless telephones will span the world; automobiles will be the universal mode of transportation; and everyone will walk ten miles a day (well, you can't win 'em all).
You don't necessarily have to go all that far back to find interesting and reasonably accurate predictions of how future technology may change our lives. For example, an article by Myron Berger, in the September 21, 1986 issue of the NY Times, describes how a new device called a "mouse" and the use of pictures on computers (such as the "pull-down menu") could revolutionize the use of computers by allowing neophytes to learn them more easily. "If computers represent the brave new world," Berger wrote, "the simplicity offered by these new products may diminish the amount of bravery many of us need to enter that world."
A lot of technologies and Web sites claim these days to be revolutionary and the lead-in to a glorious and better future. This year alone, I would put Twitter, Microsoft Vista, the iPhone, and various models of Ultra-Mobile PCs into the category of technologies that have been claimed (either by their creators, or by their adherents) to be changing the world.
It would be interesting to see, 50 or 100 years hence, which -- if any -- of these turn out to be the truly revolutionary tech.