They say talk is cheap. Google thinks it should be free. Google Talk enables you to call or send instant messages to your friends for freeâ€“anytime, anywhere in the world. Google Talk offers you:
Choice: Get in touch how and when you want toâ€“over email, IM or a call
Quality: Talk through your computer but hear your friends as if they were in the same room
Convenience: Your Gmail contacts are pre-loaded into Google Talk so inviting or talking to your friends is just a click away
Google Talk is in beta and requires a Gmail username and password.
Fast download - about 3 minutes on a modem (900K)
Requires Windows XP/2000, minimum 56k (broadband recommended)
Mac and Linux users can connect to Google Talk using other IM clients
Google Talk is not a telephony service and cannot be used for emergency dialing.
Grab it here