i always record audio using audacity, it's a free open source audio editor, just set your input to your "stereo mixer". in your preferences, set your recording to record two channels for stereo.
i tried to test it but it said "PC Users with Netscape, Mozilla or Firefox: you need to run Internet Explorer to use CMT Loaded."
soo i tried it on google video and it worked.
http://audacity.sourceforge.net/ go here to download it