If there was any doubt that that the video recording and upload capabilities of Apple’s new iPhone 3GS would signal a new chapter in mobile video sharing, the first statistics quantifying its impact are in, and they’re impressive.

Google said Thursday that in the first five days since the new Apple handset hit the market, its YouTube video sharing website saw a 400% increase in the number of video uploads coming from mobile handsets. This compares to 1700% percent growth in YouTube uploads in general over the past six months.

The iPhone 3GS is the first iPhone to support video capture and allows users to easily trim and then upload their recordings to YouTube or Apple’s MobileMe video sharing websites. Uploads are supported over both WiFi and 3G wireless connections.

Although the fourfold increase in mobile uploads to YouTube may stem early adopters familiarizing themselves with their new handsets, the iPhone 3GS remains in its infancy, having sold roughly a million units in its first week.