I've been doing some work recently on using PowerPoint for teaching and learning.
I'm going to be adding more resources here but to start here's a PowerPoint presentation (Pedagogic PowerPoint) I've added to Slide Share. It's a great site that converts your presentations to a simple slide show.
It's potentially a much better way of making your PowerPoint presentations available to students than uploading it straight to the Blackboard.
Here's a nice blog post from Clive Shephard (Don't blame PowerPoint). Usefully, it summarises some of the research done into dual code theory. It doesn't mention Tufte though who does actually blame the software and its "cognitive style".