VCASMO is a pretty neat tool to sync video and slides. Just sayin’. VCASMO syncs videos fromm youtube or similar sources, and slideshows from slideshow.com. It’s a great little mashup, the results can be embedded either 440 pixels wide (as seen above) or 850 pixels wide:
Then there’s the Adobe Air based service Parleys, which looks very slick indeed. I can’t seem to find the embed code, so I can’t really tell if it’s embeddable. Here’s a demo. (Here’s a quick run-through of Parleys.com’s publishing tool.)
Omnisio actually looked the most promising, judging by the user interface and overall smoothness. It seems, however, like Google has aqcuired the service and is integrating parts of it into YouTube, namely into YouTube annotations. Sadly, that means you cannot create new slideshows with Omnisio. Also, the annotations seemed to be the most annoying part in the demos I watched. (I turned off the annotations after a few moments each time.) Let’s see where we’ll see Omnisio again:
Update: The latter two services were added after the initial publish.