Microsoft's Windows Live Messenger

Call their phones. Call their PCs. Call your friends' mobile or landline phones.* It's affordable, both within the US and internationally. And calling someone's PC is always free. See them on the screen Show and tell: Grab a webcam and start a video conversation within minutes. Share stuff Set up a Sharing Folder with a friend. Drop in photos and other stuff, as many as your computer can handle. See your Sharing Folder even when one of you is offline. Now: Talk to your Yahoo! friends, too The world's largest IM network has just gotten bigger—and better. With Windows Live Messenger you can now connect with your Yahoo! IM contacts. Forget about using multiple accounts to talk to your friends—IM them all with Windows Live Messenger