Antares Audio Technologies has released Auto-Tune 7. In 1998 the producers of the female singer Cher used the effect successfully as their secret weapon for the track Believe. In the past decade and even today the famous Cher effect is used and abused by many popular artists.
The most important addition to Auto-Tune 7 is the new time correction and manipulation system. The time control capabilities are integrated into the graphical mode interface, which allow users to edit the timing of their vocals or other instruments right along with their pitch. There are also many smaller improvements, which you can find on the Auto-Tune information page on the Antares website.
Auto-Tune may be seen as the industrial standard, but one might question the high $400 price tag. The last decade several competitors appeared with similar functionality. For example a few sequencers now have pitch and timing correction included (Cubase, Record), or will add it soon with future updates (FL Studio).