Audacity is a very good sound recording and editing application that is open source and free. It is available for Macs, Windows, Linux and other OS from http://audacity.sourceforge.net/ Audacity is easy to use to record presentations, interviews, sounds or music. You can see a visual representation of the sampling and edit the sound kind of like a word processor, you can select a segment, delete, copy or move it. You can also record or mix several tracks and save to MP3 format for podcasting.
I have used Audacity for recording guest speakers, myself and presentations over the Internet that I was not able to attend. There are many advanced features but they are optional. The one I have found very handy is the Noise Removal effect that can clean up the buzz.
Both teachers and students will find this tool handy.
If you are interested in acquiring music for presentations, you may want to check out Finale Notepad. With this free program you can select and download from thousands of legal music pieces and record them to Audacity and put them into presentations, legally.