A good compromise may be to get an LCD panel that you drop onto an overhead projector and use like an interactive slide. They are inexpensive, lightweight, and you can probably get a used one on eBay for under US$100. But they require a bottom-lit overhead projector—the portable projectors with the light above the lens won’t work.

Truly portable LCD projectors with memory card features aren’t cheap, but you can get them for $2500 or so. Unfortunately, all of the memory card and memory stick machines that I know of convert PowerPoint slides to .jpg images for projection, so you lose all of the animation and builds. Of course, you can overcome some of that by using a lot more slides instead of builds within a slide.

If you’re looking for memory stick compatibility, you’ll need to look to Sony, as the memory stick is that company’s proprietary technology. Sony has a lightweight quality machine (the VPL-CX6) for around $2500 that lets you plug in a memory stick. Most other manufacturers use the other memory card formats (SD or CompactFlash).

You’re better off getting a Pocket PC or a PDA running Windows CE or the Palm OS and a much cheaper LCD projector. That way, you can do some last-minute edits to the presentation on the road.

Microsoft doesn’t offer a Pocket PowerPoint application (it did a couple of years ago, but discontinued it). Unless one is already bundled with your PDA, you must use a third-party software package that lets you show and edit PowerPoint presentations. You’re not going to find any mobile device or software that gives you full PowerPoint features, though, so be prepared to do without much editing power, say goodbye to sound and video, and learn to live without anything other than basic animation (in my view, that’s a plus).

There are several inexpensive (sub-$40) third-party applications that allow you to convert your desktop-created PowerPoint to a PDA-viewable format, with scaled- down functionality. You typically have to install the converter on your desktop and the viewer on your PDA, but once installed operation is often as simple as dragging a file onto the converter icon. Two examples of software are Conduit System’s Pocket Slides for Pocket PCs and Cutting Edge Software’s Quickpoint application for Palm PDAs.

Now here’s the hard part: You aren’t going to find an output port on your PDA that lets you hook up a projector cable directly, but there are interface devices that adapt existing PDA ports for that purpose. You’ll have to get such an interface from a third party vendor, or from the manufacturer of your PDA. They aren’t inexpensive, costing from $150 to $200, but they come with cabling and software. Three possibilities are the adaptor systems from Colorgraphic, I-O Data, or Margi Systems.

If you have a CompactFlash card slot on your PDA, both Colorgraphic and I-O Data provide a projector cabling system that plugs into that slot. The Colorgraphic system (called Voyager) is only a CFVGA system, so quality is good but not brilliant—no need for a high-end projector. I-O Data’s system is CFXGA, so if your presentations use a lot of photography or intricate images, I-O will give you sharper output.  Both Colorgraphic and I-O systems come with a copy of ClearVue, which contains an application for running PowerPoint presentations.