Presentations sans Powerpoint
Jessamyn West of Librarian.net has, and she has a solution: HTML slides. Not saving your PowerPoint as HTML, which leaves lots of odd coding to mess up a browser, but constructing the slides in HTML to begin with.
She has generously posted a template on her site, under a Creative Commons license. Each "slide" is a block with an HTML anchor at the top of the slide. When you click on Next, the browser flips to the next slide's anchor, giving the illusion of flipping to a different slide, but it's really just lower down in the same document. Overall, the presentation is a much smaller file. There's also a separate style sheet for printing that eliminates the bulk of the space between the slides. Be sure to read through the coding for her comments, she has a lot of great hints in there.
See her May 4, 2005 blog post for more information and the download. I'm definitely going to try it for my next presentation (with tweaking, of course. Sorry, Jessamyn, but I've never liked that background gray you use. Personally, I'm partial to blues and greens. But, each to his own background.)
Another option is Steven Cohen's blog presentation style. By posting his "slides" in reverse order (or manipulating the time stamp), Steve can put all his materials on a single page, and have a built in table of contents, thanks to the "previous posts" feature of most blog software. See his Advanced Blogging presentation from Computers in Libraries 2005. While this example doesn't use images, most blog software does allow you to post images, too. One of the intersting aspects of a blog presentation is that, if you turn the comments feature on, participants could make comments, asking questions or adding information; your presentation can become a discussion, even after the session is over.
Update: Re-reading this post, I realized that I left out another point dear to the hearts of librarians. HTML presentations will print even if you don't have PowerPoint installed on your library's public computers, and the printing CSS allows a "handout" version of the sort that won't print in some installations of the PowerPoint viewer.