Google is developing a new web browser built from the ground up and based on WebKit, the same rendering engine that Safari uses.
Google picked an interesting way of announcing the project: They commissioned illustrator Scott McCloud to draw a 38-page comic book about the project, and distribute it under a Creative Commons license. The result is a very readable, fascinating way to learn about the new browser.
Google is planning on formally launching the project on Wednesday, but the Chrome website isn't visible to the public yet. Update: Google is releasing a version for Windows tomorrow, with Mac and Linux versions coming soon, once Chrome is "faster and more robust." (Thanks, Bryan!)