PPTools
Image Export converts PowerPoint slides to high-quality images.
Shape Styles brings styles to PowerPoint. Apply complex formatting with a single click.
Merge Excel data into PowerPoint presentations to create certificates, awards presentations, personalized presentations and more
FixLinks prevents broken links when you distribute PowerPoint presentations
Optimizer saves disk space and bandwidth, "right-sizes" your PowerPoint presentations for email, screenshow or printing
PPT2HTML gives you full control of PowerPoint HTML output, helps meet Section 508 accessibility requirements
Prep4PDF preserves interactivity in PowerPoint presentations when you convert to PDF
Music clips and sounds
Here are some sources for sound files, some free, some not:
http://www.sound-effect.com
A quick search on Google or any of the other search engines will turn up dozens (hundreds!) more sites.
Please respect the copyright notices posted on these sites and be cautious about using sounds that may be posted without the permission of the copyright owner.