Thanks Stefan.
Per your advice, updated all my OS and logitech software & drivers.
During the process, logitech prompted me that while my PC specs (1.6 ghz, Pentium M laptop w 500mb ram) met its minimum requirements, they weren't "optimal" for the quickcam 9000 (*sigh*). I suspect this might be the reason for the audio cutting in and out.
As far as video goes, it's hard to tell. I might be getting a frame or 2 a second on my iPhone while on my home network wifi, but have noticed that iCam Source video frame rate is much better. Maybe there's some issues with my network/internet connection as well that might be impeding the audio (?).
Laptop's approaching its 5th birthday. Might be time to upgrade.