What is Google Wave?

Google's new Web 2.0 killer app is coming later this year: Google Wave.

Here are some links I've found that help explain what it's all about:

10 reasons why Google just reinvented online communication

Google Wave: A Complete Guide

"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."

Could Google Wave Redefine Email and Web Communication?