With that in mind, we're happy to announce the YouTube Captions Uploader open source project on Google Code, which provides real-world code for uploading captions to YouTube. The code is written for the Java App Engine environment, and it uses some nifty new App Engine features like the Channel API, the Blobstore Service, and Task Queues. And even if you're not an App Engine developer, we hope that the code that interacts with the YouTube API's captions service will provide a good starting point for writing your own code.
In addition to open sourcing the code for this project, we’re also running the code itself on a public App Engine instance, http://yt-captions-uploader.appspot.com/. So, even if you're not a developer, you can still use the application to upload captions for videos in your YouTube account.
Please share your comments or feedback via the project’s issue tracker. We hope that you find it useful both as a standalone web application and as a starting point for writing your own code!
—Jeff Posnick, YouTube API Team