I just uploaded a video made with my iPhone 3GS to youtube. Capturing video is very easy and fluid. Focus is fixed to the point when you start recording which may be an issue. Publishing a 30 second video like this one to youtube is really easy. The reencoding happens very quickly, maybe 7-8 seconds for a 30 second video. The actual upload to youtube works over 3G, you don't need Wifi. The publishing also happens in the background so you don't need to wait for it to finish. The video is decent enough quality for youtube viewing also. Very cool.
The video takes about 13.8MB on the phone so it looks around 25MB/minute encoding rate @ VGA resolution.