Google Wave is an online tool for real-time communication and collaboration.
A wave can be both a conversation
and a document where people can discuss and work together using richly formatted text, photos, videos, maps, and more.
Reference: About Google Wave
After reading this i went straight to page and thought of Registering my self for such amazing product, but sadly they only offer Membership for invited members only, though this is for short period and hopefully by end of this year they will complete the alpha version and will launch the beta version of Google Wave. by the way as a Web Designer i really liked their logo.