The OAuth support has been made more robust and future-safe, and OAuth has been added to the API. This way it’s now possible for developers to use Twitizer for uploading media the same way that it’s possible via e-mail and Browser Upload.
See http://twitizer.com/apidoc.php for information about the API. It’s TwitPic-like, with some features from TwitVid, but also simplified compared to those APIs. Hence, it should be pretty easy to understand and use.
Let us know if you want to evaluate the API. That requires a dedicated API key and information about your company, so you can’t just use it based on the documentation.
The API is immediate, meaning that when something has been submitted and the API has returned, the media upload and the optional Twitter update will have been completed as well. The only further delay can be caused by YouTube’s handling of the video, but Twitizer will at least have a landing page for the uploaded video.