tomcam

If you want to create PowerPoint slide decks for free, using nothing but a browser, and publish almost instantly to SlideShare.net, check out 280Slides. Says beta but already polished to a very high sheen. I found a few bugs, such as a broken connection to SlideShare (remedied by simply downloading your file, then uploading to SlideShare), but am loving it so far. It can also export to PDF. Links to a I created with it and to a full review.

Of course having downloaded your PPT or PDF you can then upload to sites like DocsToc and Scribd. It's super easy to publish to SlideShare but you are not limited to it.