Yes, you can insert MP3 files if you use Insert > Movies and Sounds > Sound from
File. Only WAVs are acceptable if you are trying to use a sound in a slide
transition or attached to an animation.
I have a feeling that there is more to your question. If so, please give us
more details, including your version of PowerPoint .
--
Sonia Coleman
Microsoft PowerPoint MVP Team
Autorun Software, Templates and Tutorials
http://www.soniacoleman.com