From the Official Google Blog:
Starting today, presentations -- whether imported from existing files or created using the new slide editor -- are listed alongside documents and spreadsheets in the Google Docs document list. They can be edited, shared, and published using the familiar Google Docs interface, with several collaborators working on a slide deck simultaneously, in real time. When it's time to present, participants can simply click a link to follow along as the presenter takes the audience through the slideshow. Participants are connected through Google Talk and can chat about the presentation as they're watching. Not wanting anyone to feel left out, we've made the presentation feature available in 25 languages; Google Apps customers can also access it as part of Google Docs.
I haven't tried it, but it sounds worth a check-out.