Skype 4.2.0.169/ Skype 5.0.0.105 Beta

Skype is the next phenomenon from the people who brought you KaZaA. Just like KaZaA, Skype uses P2P (peer-to-peer) technology to connect you to other users – not to share files this time, but to talk and chat with your friends. The technology is extremely advanced – but super simple to use... You’ll be making free phone calls to your friends in no time!

Yahoo! Messenger 10

Yahoo! Messenger is a popular  advertisement-supported instant messaging client and associated protocol provided by Yahoo!, that allows you to see when friends come online and to send them instant messages.

Windows Live Messenger 15

Windows Live Messenger is the next-generation MSN Messenger. It has everything you already love about Messenger - your contact list, emoticons, and instant access to your friends via text, voice, and video - plus new ways to connect and share photos and documents effortlessly. It's faster than e-mail and is a great choice for conversations and the perfect alternative when you can't be there in person. As always, it's free to download Messenger and use most of its features.