Slideshow + Podcast = Slidecasting

You can now add audio to Slideshare and embed it into websites along with the slides. They've got a nice little simple audio track along the bottom that looks a lot like the audiobook track on an iPod, and gives you a sense of where the slides change.

http://www.slideshare.net/jboutelle/slidecasting-101/

Here's a demo:
http://www.presentationzen.com/presentationzen/2007/08/now-you-can-syn.html

And here's how to make one:
http://www.jonathanboutelle.com/mt/archives/2007/07/slidecasting_th.html