This implementation of the Posterous API uses the new Google Translate Text-to-Speech capability to announce the photos being shown. Good fun!Want your own? Use this wizard to customize your Posterous slideshow.
UPDATE: There appears to be a problem with the audio for Mac users. Feel free to comment on your experience and configuration below if you're a Mac user. It will help Sharendipity track the problem down. Thanks!
UPDATE: The audio will work for Firefox users regardless of OS.