SlideFinder is a search engine for slides that I recently came across via the popular links section of Delicious. You might expect SlideFinder to search places like SlideShare and Slide Six for slides, but it doesn’t. Instead, SlideFinder searches the whole web for publicly-facing sets of slides. SlideFinder displays sets of slides in an easy-to-view grid format. SlideFinder provides a link to the host of slide sets.

Applications for Education
Before using any of the slides you or your students find via SlideFinder, make sure the way you plan to use the slides meets fair use guidelines. You should also check the source url provided by SlideFinder to see if the slides have a Creative Commons license.

Here are some related items that may be of interest to you:
12 Ways for Students to Publish Slideshows Online
Presentation Storytelling 101
Six Resources for Learning About Fair Use