Read the news: http://youtube-global.blogspot.com/2009/11/1080p-hd-comes-to-youtube.html

Any idea where to find technical details to be the first to integrate HD export to Youtube?

This is a good development for the future, but I've seen the 1080p and I have to conclude that this is premature considering the state of the web, broadband, and the average person's computer. Couldn't even stream it properly on a DSL line.

720p looks almost as good, has much smaller file sizes, less compression, streams fine over broadband etc. Most people are not going to be able to use 1080p, it's going to be a jerky slow nightmare. Even until last week with Flash player 10.1 going with video card hardware acceleration, 720p didn't even work either. Now it can look good if you have a supported video card and have the beta Flash player. Most people don't and won't for a while.

FWIW, if you look at the examples on Youtube now of 1080p, you get the specs. It's pretty similar to the Youtube 720p format with the higher res and corresponding bitrate, i.e. mp4 container, 30p, h.264 vid codec, vid bitrate of average 4600kbps, AAC audio in 44.1kHz @ ~ 128kbps.

Even if you upload a less compressed file, they are going to re-encode it down to a lower bitrate.

So the overall bitrate is below 5Mbps, whereas an AVCHD camcorder file is about 17-25Mbps. That's a LOT of compression. For reference, I render my 1080p files for computer playback with nearly the same format, but use about 20Mbps bitrate. Clearly you are not going to get anywhere near optimum 1080p quality. Honestly, 720p with less compression might actually look better. And in about 2 years Youtube will probably allow higher bitrates so you will probably want to re-upload your file.