Paige Graiser's List: Avoiding Death by Power Point

This will take you to multiple links of various sound effect libraries. The site lists them as Podcasting resources but they would also work in Power Points.

This is a great tool for designing vocabulary displays. Wordle is a toy for generating “word clouds” from text that you provide. The clouds give greater prominence to words that appear more frequently in the source text. You can tweak your clouds with different fonts, layouts, and color schemes. The images you create with Wordle are yours to use however you like. You can print them out, or save them to the Wordle gallery to share with your friends.

Its like Google for finding sound clips.