I have got a almost perfect solution for audio-video chating out of iChat with PC buddies, try the serivce from
www.ivisit.com. and you can try their free lite version which got great up to 30 frames sync with exactly your voice. if you are satisfied with it, then pay for 40 dollars for one year subsciption, which is not a affordable price for me at least, I will still keep on to the lite version, that is functions favorable to me. On other aspect the sound quality is not as good as that of video does. and we always encounter some annoyed personers there.
I am running it with QuickCam for notebook pro.