Useful links
Audacity is a free audio editor, that equals professional programs. Highly recommended if you want to record sound and edit sound files for Sequence Viewer. Flip4Mac is a free utility that allows you to play WMV files. You can download it from Microsoft or (as a free trial) from the Flip4Mac site.
With MPEG Streamclip you can convert most audio and video files to QuickTime files.
Flip4Mac
MPEG Streamclip