PBS show Nova takes a look at the science behind autotune music, and notes that the technology -- widely used in-studio and even live -- had its coming out with Cher's trancey, 1998 hit "Believe."
It appears to me that Daft Punk was using similar technology on tracks like "Around the World" in the mid-1990s, the Prodigy was laying it down in the early '90s with songs such as "Out of Space" -- although they didn't seem to have pitch correction back then -- and even such talk box taples as Zapp's "More Bounce to the Ounce" (1980) and Kraftwerk's "Autobahn" (1973) were tweaking vocals in a similar manner before the computer-recording era. Feel free to add your own recollections of vocal tweakery in the comments.
[Spotted at Entertainment Weekly].