Of course, the 'beta' label for WebDriver is somewhat late, seeing as many companies have been relying on it for at least three years, but the beta-1 was pushed out yesterday.
WebDriver started at ThoughtWorks a few years ago. Its lead, Simon Stewart, and his now Google colleagues have spent a lot of time on it since. The Selenium-1.x team (Jason Huggins, Pat Lightbody, Dan Fabulich, & many more) and new committers and friends have helped production harden WebDriver to the extent where its an admirable replacement for Selenium-RC (1.x).
There is a little brand confusion as to whether this is Selenium 2.0 or WebDriver that will resolve in time, but it is true however that Selenium 1.x will have no more major releases. That means no more Selenium-Core or Selenium-RC (other than bug fix releases). The reverse takeover that is WebDriver emulating the old Selenium is good enough for prime-time usage. Actually it has probably been good enough for some time.
Good work Simon and all involved!
Watch http://seleniumhq.org/download/ for updates.