It's definitely coming soon. As for 3.0 ready, we definitely support 3.0. That means we install on it and we do support a lot of the features. There will always be features we don't support (adding Like buttons to the Contacts manager, for instance). We always implement what we know is needed, including just the functionality to make it work on Joomla 3.0, and then we listen to feedback from users.
Hope that helps explain. We're expecting the updated Open Graph - Content plugin to be out later this month. In the mean time, you can always add the {SCOpenGraph image=http://yoursite.com/link-to-image.jpg} into the body of the article to explicitly set the image. A little more work, but flexibility that JFBConnect is built on so that things we don't directly support can be easily implemented.
Best of luck,
Alex