My department chair, one of the most technophobic people I know, actually referred me to a great web resource. Power Point Palooza is a collection of more than 200 Power Point presentations for use in history courses. The presentations are nicely categorized as US History, European History, or Global Studies.

Applications for Education
One of the best things about the Internet is all of the resources that help teachers save time. If you need a presentation for your history class on short notice, Power Point Palooza may have what you need. If you use one of the presentations from Power Point Palooza on your class blog or wiki be sure to give proper attribution.