In iPhone 3GS, the "S" stands for "speed." Among other things, it means a faster processor, but up until now, no one was really sure if the iPhone 3GS is capable of playing high definition (720p and 1080p) video. Well, now we know.
As explained on a Chinese forum, you need the free FileAid application (file manager and viewer for iPhone and iPod Touch), and you can check it out for yourself. The folks at Engadget tested a couple of HD videos, including the recently unveiled, gorgeous Avatar trailer, and though there were hiccups, it worked.
Check out the beauty of 1920x1080 pixel videos crammed into iPhone's screen in the video below.