Google's voice command has been around for a couple of years, but when the newest iPhone came out, it included Siri, a voice command app that responded to natural language requests. Most people agree that Siri was the coolest thing about the iPhone, and Siri has been highlighted in iPhone commercials.
Google, of course, wasn't going to take that lying down. And so it has upgraded its Voice Actions app. We should be seeing it by the end of the year. It basically does what Siri does, but it is cooler in two respects:
(1) Unlike with Apple, you don't have to buy a whole new phone to get it (your Honeycomb-enabled Android phone will update automatically)
(2) It's named Majel, after Majel Roddenberry, who did all the voices for all the Star Trek TV shows and movies right up until she died. Unfortunately, it's not her voice. That would be beyond awesome.