I recommend that you use either:
Both are free, but both will sometimes show advertisements on your blog.
Audacity is an open source audio editor that is available for several platforms (including Windows, Mac, and Linux/Unix). It is one of the most popular free audio editors in use today mainly due to its excellent set of tools. Download Audacity here.
Open up a YouTube account. As well as being free and the accepted online standard (although Vimeo often looks better quality) YouTube offers some functionality that we will be exploring.
Either gomockingbird or the more comprehensive gliffy will provide all the tools you need to create visual charts, wire frames, site designs and interaction maps. Use the free trial versions which will not save but you can take screen shots.