Google has finally added Presentations to their Documents and Spreadsheets, so we no longer need PowerPoint. Hurrah!

Presentations work on FireFox and Camino (and Safari soon).

There are no diagramming tools, but text can be adequately formatted. Photos can be uploaded from your PC (but not from flickr nor Google Image Search) and then resized (but not cropped).

Google shows your presentation online, letting your audience members chat via gtalk, GSS style. But none of my Mac browsers will show a slideshow fullscreen.