Just discovered (...shame, should have known it!) you can record sound and movies (including what's on the screen) with the bundled-in Quicktime Player -- don't need "Pro".
(Snow Leopard, 10.6.8)
But how do you get it to take the sound directly from EigenD without having to go via the speakers and internal microphone? Have tried fooling around with Audio Line In, in various configurations, including connecting it directly to the earphone socket. Zilch.
AFAICT Audacity & Garageband have the same limitation, which must be a Core-Audio one.