kguske writes:  

Google released Google Talk today with instant messaging and PC-to-PC voice capabilities. This comes on the heels of the recent addition of voice service for Yahoo IM and in spite of rumors that Google was courting voice-provider Skype as an acquisition.Google Talk is free, but requires a GMail account. Please provide feedback about your experiences if you try it.

My experience with Yahoo's latest service is: DON'T. I upgraded to version 7, and it crashes CONSTANTLY. I have been unable to test the voice and can no longer chat. I hope I still have an old version somewhere...