Adam nelson is writing his slides using the beamer class. the slides look fabulous.
Beamer is a latex style file which, unlike other approaches, can be processed with pdflatex
Also, last time i checked, its a standard item on most linux /osX /cygwin package managers
For notes on beamer, see http://www.math.umbc.edu/~rouben/beamer/
For an advanced guide, see http://www.math.umbc.edu/~rouben/beamer/beamer_guide.pdf
For a reason to use beamer instead of anything else, look at the zoom feature on slide 32 of http://www.math.umbc.edu/~rouben/beamer/beamer_guide.pdf: zoomable figures. Now you can include results to any level of detail.