Announced at Google I/O last year and available to Chrome beta users since February, hands-free voice search is now being rolled out to all "Chromies." The latest version of Chrome comes with the option to just say "OK Google" when opening a new tab or the Google homepage and to speak your query directly. Depending on the information being sought, Google might also respond by voice when returning the results. Though it's described as a universal update, the feature seems to only work for Chrome users with their language set to US English so far. You'll be prompted to enable it when visiting Google.com, or you can dig into the privacy settings of your browser to tick the checkbox.
Chrome now listens for 'OK Google' search commands
Chrome now listens for 'OK Google' search commands/
The latest version of Google's browser adds hands-free voice search