Beamer is a pretty nice system for putting together slick PDF slideshows with LaTeX.  In particular, it handles navigation and styling and leaves you to worry about what Really Matters: content and structure.  For an example of the end-results, you can check out the slides for dwinslow's programming talk (he didn't use the slides at the actual talk, but they are still a decent example of beamer in action.)

Basics of LaTeX

LaTeX is a system for typesetting not unlike a programming language.  You define your document's structure using a specialized syntax, run it through the LaTeX typesetting engine, and out comes a nice, consistently formatted document.  For example, a simple simple document might look like this:

\documentclass{report}
\begin{document}
Hello!
\end{document}

Words prefixed with a backslash are latex commands, which often take a chunk of text to operate upon.  In this document, we use the documentclass command to define our document as a report, and then the begin and end commands to enclose the actual document text. 

Beamer-ing it Up

In order to define a document as a presentation, you simple declare the document class as "beamer" without the quotes.  There are quite a few commands you can use in a Beamer presentation, but some of the most important are outlined in the attached presentation template.  Make sure to put it in the same directory with the accompanying topplogo.jpg.  You can build it with

pdflatex mypresentation.tex

if latex and beamer are properly installed on your system.

More Information

If you want to get really handy with Beamer, there's an excellent tutorial available online.  It also doubles as a pretty decent guide on how to construct a presentation. You can also talk to dwinslow, he's a pretty big advocate of Beamer.