Google Talk

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Download Free Google Talk 1.0.0.104

Google Talk: All you need to make free calls is an Internet connection, a microphone, and a speaker. After you download Google Talk, you'll need to sign in with your Gmail username and password. Then you can invite your friends to download Google Talk, and once they do, you'll be able to talk or IM with them instantly.

Benefits of Google Talk:
Once your friends download Google Talk, you can talk to them anytime they're online
Your Gmail contacts are pre-loaded into Google Talk
Talk via voice or instant messaging
No adverts or pop-ups
Easily send files of any size
Leave voicemail messages if someone is not online
Displays your currently playing song in your friends contact list (supported players only)
Exchange instant messages with other clients supporting the standard XMPP protocol.