Remember the Publish → More Services in Live Photo Gallery ? Other than Flickr, we’re promised an extensibility. For the developers, there are API you can use to build plug in. For most of us programming-illiterate, we’re promised eventually there will be.
The plug-ins are, LiveUpload to Facebook and LiveUpload to YouTube. This enable you to publish your photo or video to the two online services, just like you could publish to Spaces and Flickr. :)