Interesting idea:

Presente3D is an easy to use add-on for Microsoft PowerPoint that allows you to easily take any existing MS PowerPoint slide and make it 3D in minutes.

via Presente 3D adds Stereo to PowerPoint for $59.

For now, a niche market, but an interesting idea as glass free displays begin to become common. Although, if this takes off, undoubtedly Microsoft would add similar 3D support directly to Powerpoint – or by up this company 🙂