Can some 1 tell me about Google wave?

[Shilpa Singh]

Google Wave is a real-time communication platform. It combines aspects of email, instant messaging, wikis, web chat, social networking, and project management to build one elegant, in-browser communication client. You can bring a group of friends or business partners together to discuss how your day has been or share files.
Open source:: The Google Wave code will be open source, to foster innovation and adoption amongst developers.
Yes you can use it , you need to have invitation by someone to get an account in google wave.
Please feel free to chk this article for more details http://www.himshilp.com/seo-articles/google-wave.htm