We've been working on a new API based on the Google data protocol over the last few months, and our first version has now been released into the wild. If you want to build a cool YouTube mashup or programmatically add YouTube content to your site, this is a great time to get started with our API.
We've also set up a migration guide for all the developers who are using the old REST/XML-RPC API. The Legacy API will continue to work for at least a year -- through August 30, 2008, but we encourage developers to switch early and to give feedback on the new API.
Please head over to the API Announcement Blog for more info on this release. We also welcome new members to the developer community, so come join the forum if you're interested.
The YouTube Team