The "OK Google" voice activated hot search has gradually been making its way up the Google Chrome food chain, and now it looks like its rolling out to all. Well, all so long as you've set your language to U.S. English at least, or so it seems.
The listening search box should be present after the latest update on both the Google homepage and when you open up a new browser tab. It's always listening so just say the magic words and you're off with some hands-free Googling. Have fun with that!
Source: +Google Chrome