Microsoft Powerpoint is presentation software - that is, software designed to allow one to combine words, images, sound, animation, and other things together, to be used by speakers who want to “present” data to an audience.
See vebklaso or ewipe for alternative presentation programs. Another option is Impress, which is part of the OpenOffice.org suite.
For tcl-only programs see:
DKF: Also consider generating suitable HTML or PDF documents; colleagues of mine have had success with both strategies for simpler presentations.
D. McC 2009/01/04: For those who don't mind forking over a modest amount of money (much less than M$ demands) for commercial software on occasion, there's SoftMaker Presentations 2008, part of the SoftMaker Office suite (see http://www.softmaker.de ), available for Windows, Linux, and a couple of OS's for handheld devices.