Audacity is free, open source, cross-platform software for recording and editing sounds.

How it is useful to technical communicators:

Audacity can be used to add/edit audio when working on video assignments. It provides more audio manipulation techniques that are not available through video software.

Where you can learn more about it:

You can learn more about Audacity and download the software through the Audacity website.

Other software like it:

Adobe Audition