Empressr is a presentation/slideshow tool that lets you use a variety of audiovisual content (video, audio, pictures, Flash, charts, and graphs). You make the presentation on-line and can embed it on a web page or somewhere like a blog.

It's very much like Google's application but has nice templates and several extra effects that make it worth a look.

There are many samples on the site, some good and some not so good (what is with people who feel they have to add piles of text to slides?) This one just has photos but is a good example of what can be done simply, with just a netbook and no software.