Unless you've been on a secluded island for the last 10 years, you would have definately heard about the IM or Instant Messenger craze. The two most popular providers would be Microsoft with their MSN/Windows Messenger client and also Yahoo! with their Yahoo Messenger server. Some other clients like the once popular ICQ have fallen out of favour.
Google Inc is now jumping onboard the IM bandwagon (they are jumping on everything that moves) and have released a beta of their own IM client aptly named Google Talk. It links back with your gmail account, so if you already have one, then you can login and start inviting your friends to join in. Its very basic - which would appeal to quite a lot of us who want an IM to just exchange messages rather then have fancy images and backgrounds with unnecessary functions. Google seems to be keeping to their style of keeping everything simple and effective.