Tweetscan FTW. Does a great job and you can filter based on user. I think *including* Twitter results in Google may get a little chaotic but if Google were to buy / make a tweetscan clone and integrate it as a setting on your google search - that would be sweet. ( optional results show up )
I did a bit of Googling myself yesterday and its interesting that many of the sites that work off of the API are pulling results. So if I search for "pixelbud" I get a lot of results for my twitter convos via sites such as http://quotably.com/ or even http://twittervision.com/