I've been working with the Youtube API - http://code.google.com/apis/youtube/2.0/developers_guide_php.html - over the weekend, and have discovered that the documentation is not exactly up to date, and some things just dont work.
I may have to resort to the Drupal module - http://drupal.org/project/youtube_api/ - Even though it looks a little neglected, at least I can fix and send patches back to that.
Google's catchup to facebook connect is in action still, with updates/releases to the API made yesterday to allow better integration with other services.
In particular I was interested in using it with Drupal, and found this post: http://code.google.com/p/google-friend-connect-plugins/wiki/DrupalPlugin which was just updated on the 12th, so should be a very good introduction, and there is a drupal module already, which is great.
I'll try it out later and write another blog post.