Dan Moren at Macworld quotes the figures:
In a post on the YouTube blog product manager Dwipal Desai and community manager Mia Quagliarello say that the number of videos uploaded to the sharing site from mobile phones has jumped 400 percent a day since the iPhone 3GS’s release last Friday.
As part of an overall 1700% increase year to date, you don't have to be Oliva Munn and Kevin Peirera (NSFW-L) to know how much the quick and easy shooting and uploading of video to YouTube via the iPhone 3GS will continue to push that. Truth be told, we think Apple just unleashed a TMZ-style hurting on reckless celebrities and unfortunate public fool-of-themselves'ers like the world ain't never seen before.
Little brother indeed.