If you use LaTeX, and you want to give PowerPoint-style presentations, don't despair. At least for simple presentations, it's pretty easy. Just follow these instructions (which assume you are working in a Unix/Linux environment).
Have a look at the file simpletalk.tex for the basic template of a simple presentation. Note that it use the package foils.
Make sure you have installed the package foils, which you can download here. (See the readme file for installation instructions.)
Process the file:
Command
Purpose
latex simpletalk.tex
Convert source code to DVI.
dvips -t a4 -t landscape simpletalk.dvi
Convert DVI to Postscript.
ps2pdf simpletalk.ps
Convert Postscript to PDF.
Notes
Don't go from .tex directly to .pdf (using e.g. pdflatex) because various things that use Postscript won't work--e.g., tree-dvips. (For more on producing trees in LaTeX, try The Guide to LaTeX for Linguists
To view the output files, you can use any one of a number of programs: e.g., xdvi (.dvi), ghostview (.ps or .pdf), Adobe acrobat (.pdf).