Googlers Mike LeBeau, who is in charge of search within Glass and Amanda Rosenberg, the product manager of Glass, produced a video showing you what it is like to search Glass for things.
It is pretty impressive and you can get a really good idea of how it works in this 3 minute video.
Mike said on Google+:
One thing that makes Glass awesome is that you can just long press on the touchpad any time and speak to ask Google a question. It’s a super fast way to search which, it turns out, is pretty magical.
+Amanda Rosenberg and I decided to test out a bunch of cool searches and thought you guys would like 'em too - check it out.
Here is the video:
Forum discussion at Google+.