iPhone 3G S comes with typical shiny white Apple headset buds, but for the first time these earbuds sport the new "remote", which includes volume controls and more.
Apple previously introduced iin-ear headsets with remote and mic for the second generation iPod touch (and aluminum MacBooks) in September 2008, but clearly labeled them as not-compatible with the iPhone 2G or iPhone 3G because the "remote" part was useless.
What a different a generation makes.
Now the full control scheme introduced with the 4th gen iPod shuffle is available to iPhone 3G S owners with one notable difference -- holding down the center button activates Voice Control.
(Thanks Bruce for the tip!)